Systems and methods for signaling of information associated with audio content

ABSTRACT

A device may be configured to parse a syntax element specifying the number of available languages within a presentation associated with an audio stream. A device may be configured to parse one or more syntax elements identifying each of the available languages and parse an accessibility syntax element for each language within the presentation.

TECHNICAL FIELD

The present disclosure relates to the field of interactive television.

BACKGROUND ART

Digital media playback capabilities may be incorporated into a widerange of devices, including digital televisions, including so-called“smart” televisions, set-top boxes, laptop or desktop computers, tabletcomputers, digital recording devices, digital media players, videogaming devices, cellular phones, including so-called “smart” phones,dedicated video streaming devices, and the like. Digital media content(e.g., video and audio programming) may originate from a plurality ofsources including, for example, over-the-air television providers,satellite television providers, cable television providers, online mediaservice providers, including, so-called streaming service providers, andthe like. Digital media content may be delivered over packet-switchednetworks, including bidirectional networks, such as Internet Protocol(IP) networks and unidirectional networks, such as digital broadcastnetworks.

Digital media content may be transmitted from a source to a receiverdevice (e.g., a digital television or a smart phone) according to atransmission standard. Examples of transmission standards includeDigital Video Broadcasting (DVB) standards, Integrated Services DigitalBroadcasting Standards (ISDB) standards, and standards developed by theAdvanced Television Systems Committee (ATSC), including, for example,the ATSC 2.0 standard. The ATSC is currently developing the so-calledATSC 3.0 suite of standards. The ATSC 3.0 suite of standards seek tosupport a wide range of diverse services through diverse deliverymechanisms. For example, the ATSC 3.0 suite of standards seeks tosupport broadcast multimedia delivery, so-called broadcaststreaming/file download multimedia delivery, so-called broadbandstreaming/file download multimedia delivery, and combinations thereof(i.e., “hybrid services”). An example of a hybrid service contemplatedfor the ATSC 3.0 suite of standards includes a receiver device receivingan over-the-air video broadcast (e.g., through a unidirectionaltransport) and receiving a synchronized secondary audio presentation(e.g., a secondary language) from an online media service providerthrough a packet network (i.e., through a bidirectional transport).Currently proposed techniques for supporting audio content may be lessthan ideal.

SUMMARY OF INVENTION

In general, this disclosure describes techniques for signaling (orsignalling) information associated with audio content associated with aservice. It should be noted that audio content may be included as partof an audio-visual service (e.g., television programming) or in someexamples may be included as a dedicated audio service (e.g., radioprogramming). It should be noted that although in some examples thetechniques of this disclosure are described with respect to ATSCstandards and particular audio standards and formats, the techniquesdescribed herein may be generally applicable to any transmissionstandard and audio standard or format. For example, the techniquesdescribed herein may be generally applicable to any of DVB standards,ISDB standards, ATSC Standards, Digital Terrestrial Multimedia Broadcast(DTMB) standards, Digital Multimedia Broadcast (DMB) standards, HybridBroadcast and Broadband Television (HbbTV) standards, World Wide WebConsortium (W3C) standards, Universal Plug and Play (UPnP) standards,and other video encoding standards. Further, it should be noted thatincorporation by reference of documents herein is for descriptivepurposes and should not be constructed to limit and/or create ambiguitywith respect to terms used herein. For example, in the case where oneincorporated reference provides a different definition of a term thananother incorporated reference and/or as the term is used herein, theterm should be interpreted in a manner that broadly includes eachrespective definition and/or in a manner that includes each of theparticular definitions in the alternative.

According to one example of the disclosure, a method for signalinginformation associated with an audio stream comprises signaling a syntaxelement specifying the number of available languages within apresentation associated with an audio stream and signaling one or moresyntax elements identifying each of the available languages.

According to another example of the disclosure, a device for signalinginformation associated with an audio stream comprises one or moreprocessors configured to signal a syntax element specifying the numberof available languages within a presentation associated with an audiostream and signal one or more syntax elements identifying each of theavailable languages.

According to one example of the disclosure, a method for parsinginformation associated with an audio stream, comprises parsing a syntaxelement specifying the number of available languages within apresentation associated with an audio stream and parsing one or moresyntax elements identifying each of the available languages.

According to one example of the disclosure, a method for signalinginformation associated with an audio stream associated with emergencyinformation, the method comprising signaling a syntax element indicatingthe audio stream is associated with emergency information; and signalingone or more syntax elements identifying timing information of theemergency information.

According to one example of the disclosure, a method for parsinginformation associated with an audio stream, the method comprisingparsing a syntax element indicating the audio stream is associated withemergency information; and parsing one or more syntax elementsidentifying timing information of the emergency information, upondetermining the audio stream is associated with emergency information.

The details of one or more examples are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram illustrating an example of contentdelivery protocol model according to one or more techniques of thisdisclosure.

FIG. 2A is a conceptual diagram illustrating an example of respectivedelivery mechanisms of a media service according to one or moretechniques of this disclosure.

FIG. 2B is a conceptual diagram illustrating an example of a streamdelivery mechanism of a media service according to one or moretechniques of this disclosure.

FIG. 3 is a block diagram illustrating an example of a system that mayimplement one or more techniques of this disclosure.

FIG. 4 is a block diagram illustrating an example of a servicedistribution engine that may implement one or more techniques of thisdisclosure.

FIG. 5A is a block diagram illustrating an example of a componentencapsulator that may implement one or more techniques of thisdisclosure.

FIG. 5B is a block diagram illustrating an example of a componentencapsulator that may implement one or more techniques of thisdisclosure.

FIG. 6 is a block diagram illustrating an example of a receiver devicethat may implement one or more techniques of this disclosure.

DESCRIPTION OF EMBODIMENTS

Computing devices and/or transmission systems may be based on modelsincluding one or more abstraction layers, where data at each abstractionlayer is represented according to particular structures, e.g., packetstructures, modulation schemes, etc. An example of a model includingdefined abstraction layers is the so-called Open Systems Interconnection(OSI) model illustrated in FIG. 1. The OSI model defines a 7-layer stackmodel, including an application layer, a presentation layer, a sessionlayer, a transport layer, a network layer, a data link layer, and aphysical layer. It should be noted that the use of the terms upper andlower with respect to describing the layers in a stack model may bebased on the application layer being the uppermost layer and thephysical layer being the lowermost layer. Further, in some cases, theterm “Layer 1” or “L1” may be used to refer to a physical layer, theterm “Layer 2” or “L2” may be used to refer to a link layer, and theterm “Layer 3” or “L3” or “IP layer” may be used to refer to the networklayer.

A physical layer may generally refer to a layer at which electricalsignals form digital data. For example, a physical layer may refer to alayer that defines how modulated radio frequency (RF) symbols form aframe of digital data. A data link layer, which may also be referred toas link layer, may refer to an abstraction used prior to physical layerprocessing at a sending side and after physical layer reception at areceiving side. As used herein, a link layer may refer to an abstractionused to transport data from a network layer to a physical layer at asending side and used to transport data from a physical layer to anetwork layer at a receiving side. It should be noted that a sendingside and a receiving side are logical roles and a single device mayoperate as both a sending side in one instance and as a receiving sidein another instance. A link layer may abstract various types of data(e.g., video, audio, or application files) encapsulated in particularpacket types (e.g., Motion Picture Expert Group-Transport Stream(MPEG-TS) packets, Internet Protocol Version 4 (IPv4) packets, etc.)into a single generic format for processing by a physical layer. Anetwork layer may generally refer to a layer at which logical addressingoccurs. That is, a network layer may generally provide addressinginformation (e.g., Internet Protocol (IP) addresses) such that datapackets can be delivered to a particular node (e.g., a computing device)within a network. As used herein, the term network layer may refer to alayer above a link layer and/or a layer having data in a structure suchthat it may be received for link layer processing. Each of a transportlayer, a session layer, a presentation layer, and an application layermay define how data is delivered for use by a user application.

Transmission standards, including transmission standards currently underdevelopment, may include a content delivery protocol model specifyingsupported protocols for each layer and may further define one or morespecific layer implementations. Referring again to FIG. 1, an examplecontent delivery protocol model is illustrated. In the exampleillustrated in FIG. 1, content delivery protocol model 100 is “aligned”with the 7-layer OSI model for illustration purposes. It should be notedthat such an illustration should not be construed to limitimplementations of the content delivery protocol model 100 or thetechniques described herein. Content delivery protocol model 100 maygenerally correspond to the currently proposed content delivery protocolmodel for the ATSC 3.0 suite of standards. Further, the techniquesdescribed herein may be implemented in a system configured to operatebased on content delivery protocol model 100.

Aspects of the ATSC 3.0 suite of standards currently under developmentare described in Candidate Standards and Working Drafts, which mayinclude proposed aspects for inclusion in a published (i.e., “final” or“adopted”) version of an ATSC 3.0 standard. For example, ATSC CandidateStandard: Physical Layer Protocol, Doc. S32-230r21, 28 Sep. 2015, whichis incorporated by reference in its entirety, describes specificproposed aspects of an ATSC 3.0 unidirectional physical layerimplementation. The proposed ATSC 3.0 unidirectional physical layerincludes a physical layer frame structure including a defined bootstrap,preamble, and data payload structure including one or more physicallayer pipes (PLPs). A PLP may generally refer to a logical structurewithin an RF channel or a portion of an RF channel. That is, a PLP mayinclude a portion of an RF channel having particular modulation andcoding parameters. The proposed ATSC 3.0 unidirectional physical layerprovides that a single RF channel can contain one or more PLPs and eachPLP may carry one or more services. In one example, multiple PLPs maycarry a single service. In the proposed ATSC 3.0 suite of standards, theterm service may be used to refer to a collection of media componentspresented to the user in aggregate (e.g., a video component, an audiocomponent, and a sub-title component), where components may be ofmultiple media types, where a service can be either continuous orintermittent, where a service can be a real time service (e.g.,multimedia presentation corresponding to a live event) or a non-realtime service (e.g., a video on demand service, an electronic serviceguide service), and where a real time service may include a sequence oftelevision programs. Further, the proposed ATSC 3.0 suite of standardsdefines five service categories as follows: (1) A “linear audio/videoservice” is a service consisting of one or more continuous videocomponents, one or more continuous audio components, each associatedwith one or more of the video components, and one or more closed captioncomponents, each associated with one or more of the audio components,all streamed in real time. May also contain app-based features; (2) A“linear audio-only service” is a service consisting of one or morecontinuous audio components and one or more closed caption components,each associated with one or more of the audio components, all streamedin real time. May also contain app-based features; (3) An “app-basedservice” is a service consisting entirely of app-based features, whichprovide the user interface for the service; An App-Based Feature is aservice component consisting of an application, optional files to beused by the application, and optional notifications directing theapplication to take particular actions at particular times; (4) An “ESG(ESG) service (program guide) service” is a service that deliversElectronic Service Guide information; and (5) An “Emergency Alert (EA)service” provides emergency alerting information (text and, ifavailable, associated video and/or audio content) and rich mediaresources that are referenced in emergency information messages. In oneexample, an application may be a collection of documents constituting anenhanced or interactive service. The documents of an application mayinclude HTML, JavaScript, CSS, XML and multimedia files. It should benoted that the proposed ATSC 3.0 suite of standards specifies that newtypes of services may be defined in future versions. Thus, as usedherein the term service may refer to a service described with respect tothe proposed ATSC 3.0 suite of standards and/or other types of digitalmedia services.

A service (e.g., a linear audio/video service) may include emergencyinformation. In one example, emergency information may be defined asinformation, about a current emergency, that is intended to further theprotection of life, health, safety, and property, including criticaldetails regarding the emergency and how to respond to the emergency.Examples of the types of emergencies covered include tornadoes,hurricanes, floods, tidal waves, earthquakes, icing conditions, heavysnows, widespread fires, discharge of toxic gases, widespread powerfailures, industrial explosions, civil disorders, and warnings andwatches of impending changes in weather. Emergency information may bedisplayed in video as text (which may be referred to as emergencyon-screen text information), and may include, for example, a scrollingbanner (which may be referred to as a crawl). Signaling may be neededfor emergency information to support a separate audio component providedby the broadcaster during the display of the scrolling banner. Signalingmay need to occur at the start of message and also signal the end ofmessage. This signaling could enable the capabilities in a receiver toallow a visually impaired viewer to manually select the emergencyinformation audio component into the decoded output and/or allow a userpreference setting so that a receiver could retain and act on the userpreference. In the latter case, the signaling of the presence of anactive audio component may be essential. In one example, an emergencyinformation audio component may be different from a non-real-time audiofile, which may be part of the enhanced alert information, or a separatemain audio. In some examples, emergency information may includeinformation that is distinct from information provided through anemergency alert service. In one example, audio for an emergency alertmay be included in main audio. In one example, the start/end time ofaudio/aural representation of the emergency information and thecorresponding video crawl may not be aligned. In one example, thestart/end time of audio/aural representation of the emergencyinformation and the corresponding video crawl may be partially aligned.In one example, the start/end time of audio/aural representation of theemergency information and the corresponding video crawl may be aligned.

Referring to FIG. 1, content delivery protocol model 100 supportsstreaming and/or file download through the ATSC Broadcast Physical layerusing MPEG Media Transport Protocol (MMTP) over User Datagram Protocol(UDP) and Internet Protocol (IP) and Real-time Object delivery overUnidirectional Transport (ROUTE) over UDP and IP. MMTP is described inISO/IEC: ISO/IEC 23008-1, “Information technology-High efficiency codingand media delivery in heterogeneous environments-Part 1: MPEG mediatransport (MMT),” which is incorporated by reference herein in itsentirety. An overview of ROUTE is provided in ATSC Candidate Standard:Signaling, Delivery, Synchronization, and Error Protection (A/331) Doc.532-174r1, 5 Jan. 2016 (hereinafter “A/331”), which is incorporated byreference in its entirety. It should be noted that although ATSC 3.0uses the term broadcast to refer to a unidirectional over-the-airtransmission physical layer, the so-called ATSC 3.0 broadcast physicallayer supports video delivery through streaming or file download. Assuch, the term broadcast as used herein should not be used to limit themanner in which video and associated data may be transported accordingto one or more techniques of this disclosure.

In the case where MMTP is used for streaming and/or file downloadthrough the ATSC Broadcast Physical layer, service component data (e.g.,video data, audio data, closed caption data, etc.) may be encapsulatedin a Media Processing Unit (MPU). MMTP defines a MPU as “a media dataitem that may be processed by an MMT entity and consumed by thepresentation engine independently from other MPUs.” A logical groupingof MPUs may form an MMT asset, where MMTP defines an asset as “anymultimedia data to be used for building a multimedia presentation. Anasset is a logical grouping of MPUs that share the same asset identifierfor carrying encoded media data.” For example, for a video component,MPUs may include groups of pictures (GOPs) that are independentlydecodable and an asset may include several MPUs forming a videosequence. One or more assets may form a MMT package, where a MMT packageis a logical collection of media content. For example, an MMT packagemay include an asset corresponding to a video component and an assetcorresponding to an audio component. It should be noted that A/331provides the following definitions for Asset, Media Processing Unit andMMT Package:

‘Asset’—Any multimedia data entity that is associated with a uniqueidentifier and that is used for building a multimedia presentation.

‘Media Processing Unit’—Generic container for independently decodabletimed or non-timed data that is media codec agnostic

‘MMT Package’—Logical collection of media data, delivered using MMT.

As used herein the terms asset, media processing unit, and MMT Packagemay be inclusion of definitions provided in A/331 and MMTP in a generalmanner and/or may include respective definitions in the alternative.A/331 provides that a single MMT package can be delivered over one ormore MMTP sessions, where each MMTP session can be identified by adestination IP address and a destination UDP port number. Further, A/331provides that multiple MMT packages can be delivered by a single MMTPsession. A/331 provides that each PLP can carry one or more MMTPsessions. In addition, A/331 provides that one MMTP session can becarried by more than one PLP. Further, it should be noted that packetsincluding MPUs and/or MPU fragment may form a stream.

In the case where ROUTE is used for streaming and/or file downloadthrough the ATSC Broadcast Physical layer, service component data (e.g.,video data, audio data, closed caption data, etc.) may be encapsulatedin a Dynamic Adaptive Streaming over Hypertext Transport Protocol (HTTP)(DASH) Media Presentation (i.e., ROUTE/DASH). Further, service componentdata may be associated with one or more segments carried over LayerCoding Transport (LCT) channels. In some cases, an LCT channel may beconceptually similar to an MMT asset and/or segments may be conceptuallysimilar to MPUs. That is, for media delivery, an LCT channel may carryas a whole, or in part, a media component and a ROUTE session may beconsidered as the multiplex of LCT channels that carry constituent mediacomponents of one or more media presentations. That is, each ROUTEsession may include one or more LCT channels, where LCT channels aresubsets of a ROUTE session. Further, A/331 provides that one or more LCTchannels may be included in a PLP and as such, a ROUTE session may becarried by one or more PLPs. Further, similar to a MMTP session, A/331provides that a ROUTE session may be identified by a destination IPaddress and a destination UDP port number. It should be noted that aROUTE session may further be identified by a source IP address.

As described above, aspects of the ATSC 3.0 suite of standards currentlyunder development are described Working Drafts. ATSC Working Draft:Audio, Part 1: Common Elements Doc. 34-2-235r9 (herein after “ATSC AudioWD”), which is incorporated by reference herein, describes an AudioProgram as the complete collection of all Audio Program Components and aset of accompanying Audio Presentations that are available for one AudioProgram, where an Audio Presentation is a set of Audio ProgramComponents representing a version of the Audio Program that may beselected by a user for simultaneous decoding and an Audio ProgramComponent is a logical group of one or more Audio Elements that is usedto define an Audio Presentation. In the ATSC Audio WD, Audio elementsare defined as the smallest addressable unit of an Audio Program and mayconsist of one or more Audio Signals, where an Audio Signal is a monosignal. In the ATSC Audio WD, Audio element format corresponds to thedescription of the configuration and type of an Audio Element. There arethree different types of Audio Element Formats. Depending on the type,different kinds of properties are used to describe the configuration:Channel-based audio: e.g., the number of channels and the channellayout; Object-based audio: e.g., dynamic positional information;Scene-based audio: e.g., Higher Order Ambisonics (HOA) order, number oftransport channels. In one example, an Audio Program may include anEnglish language dialogue Audio Program Component, a Spanish languagedialogue Audio Program Component, and a music and effects Audio ProgramComponent. Each program component may include one or more audiochannels. For example, Audio Program Components may be in stereo (i.e.,a so-called “2.0” presentation including left and right audio channels)or may be in a surround sound format (e.g., 5.1 audio), or the like. Inone example, with respect to the audio program components above, Englishlanguage dialogue Audio Program Component and music and effects AudioProgram Component may form an English language presentation and Spanishlanguage dialogue Audio Program Component and music and effects AudioProgram Component may form a Spanish language presentation. Thus, anaudio presentation may be described as a logical grouping of AudioElements, where Audio Elements form Audio Program Components. It shouldbe noted that ATSC Audio WD contemplates that different terminology maybe used with respect to describing audio data and includes Table 1 inorder to relate terms to one another.

TABLE 1 MPEG-H (ISO Dolby AC-4 IEC 23008-3) Common Term DASH Term TermAudio Term Audio Presentation Preselection Presentation Preset AudioProgram Bundle Audio Program Audio Scene Audio Program Referred to asAudio Program Group Component Audio Element Component

As used herein the terms audio presentation, audio program, and audioprogram component may, in some examples, be inclusive of correspondingterms used to describe similar structures in other audio systems. Asdescribed above, one or more assets including MPUs may form a MMTpackage packets that include MPUs and/or fragments thereof may form astream. In one example, an audio stream may be formed as a group ofpackets including MPUs encapsulating audio data. FIG. 2A is a conceptualdiagram illustrating respective delivery mechanisms of a service as anMMT package and a service as DASH media presentation. FIG. 2Aillustrates additional detail of audio assets that may be included aspart of an MMT package. In the example, illustrated in FIG. 2A, eachaudio asset may correspond to the example Audio Program Componentsdescribed above. FIG. 2B further illustrates the grouping of the MPUs(or fragments thereof) included in the assets illustrated in FIG. 2A,included in an audio stream. That is, a receiver receiving packetsincluded in an audio stream may parse the packets into assets. It shouldbe noted that the example illustrated in FIGS. 2A-2B is for descriptivepurposes and should not be constructed to limit the scope of thetechniques described herein.

Referring again to FIG. 2A, for each respective delivery mechanismcorresponding service layer signaling occurs. In general, service layer(or level) signaling (SLS) may include information that enables areceiver to discover and/or access user services and their contentcomponents. A/331 provides specific data structures that may be includedas part of a service layer signaling. That is, A/331 defines a set ofmessage formats to be used to communicate signaling informationnecessary for the delivery and consumption of services by a receiverdevice. Referring to FIG. 2A, for service layer signaling with respectto a MMTP delivery mechanism, A/331 service layer signaling includes aUser Service Bundle Descriptor (USBD) and MMT specific signalingmessages. For the sake of brevity, the format of the USBD for MMT is notdescribed herein, however, reference is made to A/331. It should benoted that in one example, receiver devices may be expected to disregardreserved values, and unrecognized or unsupported descriptors, XMLattributes and elements. In one example, reserved fields are reservedfor future use and receiving devices conforming to the definedspecification are expected to disregard reserved fields.

In addition to including one or more assets, a MMT package includespresentation information (PI) and asset delivery characteristics (ADC).Presentation information includes documents (PI documents). A PIdocument may be delivered as one or more signalling messages. Assetdelivery characteristics describe the quality of service (QoS)requirements and statistics of assets for delivery. PIs and ADCs may beassociated with one or more assets and MPUs encapsulated therein. MMTspecifies a signaling function that defines a set of message formats forsignaling messages. MMT specifies message formats for carrying signalingtables, descriptors or delivery related information. Table 2 providesthe syntax of the general format of MMT signaling messages. It should benoted that in Table 2, and other tables included in this description,uimsbf refers to an unsigned integer most significant bit first datatype. Further, bslbf refers to a bit string, left bit first data type.

TABLE 2 Syntax Value No. of bits Mnemonic signalling_message ( ) {  message_id 16 uimsbf   version 8 uimsbf   if(message_id != PA_message&& message_id != MPI_message) {   length 16 uimsbf   } else {   length32 uimsbf   }   extension   message_payload {   } }

MMT provides the following definitions for syntax elements ‘message_id’,‘version’, ‘length’, ‘extension’, ‘message_payload’:

‘message_id’—this field indicates the identifier of the signallingmessage. [In one example] Valid message identifier values are listed inTable 34 [of MMT].

‘version’—this field indicates the version of the signalling message.Both MMT sending entity and MMT receiving entity can verify whether areceived message has a new version of not.

‘length’—this field indicates the length of the signalling message. Thisfield for all signalling message except Package Access (PA) messages andMedia Presentation Information (MPI) message is 2 bytes long. The lengthof PA messages and MPI messages is 4 bytes long because it is expectedthat occasionally an MPI table whose length cannot be expressed by a 2bytes length fields. Also note that a PA message includes at least oneMPI table.

‘extension’—this field provides extension information for signallingmessages that require extension. The content and length of this fieldare specified for these signalling messages.

‘message payload’—the payload of the signalling message. The format ofthis field can be identified by the value of the message_id field.

As illustrated in Table 2, a message may be identified using a messageidentifier value. In MMT, message identifier values of 0x8000 to 0xFFFFmay be reserved for private use. A/331 defines a MMT signaling message(e.g., mmt_atsc3_message( )), where a MMT signaling message is definedto deliver information specific to ATSC 3.0 services. A MMT signalingmessage may be identified using a MMT message identifier value reservedfor private use (e.g., a value of 0x8000 to 0xFFFF). Table 3 providesexample syntax for a MMT signaling message mmt_atsc3_message( ).

TABLE 3 No. of Syntax Bits Format mmt_atsc3_message( ) {   message_id 16uimsbf   version 8 uimsbf   length 32 uimsbf   message payload {    service_id 16 uimsbf     atsc3_message_content_type 8 uimbsf    atsc3_message_content_version 8 uimbsf    atsc3_message_content_compression 8 uimbsf     URI_length 8 uimbsf    for (i=0;i< URI_length;i++) {       URI_byte 8 uimsbf     }    atsc3_message_content_length 32 uimsbf     for(i=0;i<atsc3_message_content_length;     i++) {      atsc3_message_content_byte 8 uimsbf     }      for(i=0;i<length-10-URI_length-      atsc3_message_content_length) {      reserved 8 uimsbf     }   } }

A/331 provides the following definitions for syntax elements‘message_id’, ‘version’, ‘length’, ‘service_id’,‘atsc3_message_content_type’, ‘atsc3_message_content_version’,‘atsc3_message_content_compression’, ‘URI_length’, ‘URI_byte’,‘atsc3_message_content_length’, ‘atsc3_message_content_byte’, ‘andreserved’:

‘message_id’—A 16-bit unsigned integer field that shall uniquelyidentify the mmt_atsc3_message( ). The value of this field shall be0x8000.

‘version’—An 8-bit unsigned integer field that shall be incremented by 1any time there is a change in the information carried in this message.When the version field reaches its maximum value of 255, its value shallwraparound to 0.

‘length’—A 32-bit unsigned integer field that shall provide the lengthof mmt_atsc3_message( ) in bytes, counting from the beginning of thenext field to the last byte of the mmt_atsc3_message( ).

‘service_id’—A 16-bit unsigned integer field that shall associate themessage payload with the service identified in the serviceId attributegiven in the Service Labeling Table (SLT).

‘atsc3_message_content_type’—A 16-bit unsigned integer field that shalluniquely identify the type of message content in the mmt_atsc3_message() payload, coded per Table [4] below.

TABLE 4 atsc3_message_content_type Meaning 0x0000 Reserved 0x0001 A UserService Bundle Description Fragment for MMT 0x0002 An Media PresentationDescriptor (MPD) 0x0003 An Application Information Table 0x0004Application Event Information 0x0005 Video Stream Properties Descriptor0x0006 An ATSC Staggercast Descriptor 0x0007 An Inband Event Descriptor0x0008 Caption Asset Descriptor 0x0009~0xFFFF Reserved for future use

‘atsc3_message_content_version’—An 8-bit unsigned integer field thatshall be incremented by 1 any time there is a change in theatsc3_message content identified by a service_id andatsc_message_content_type pair. When the atsc3_message_content_versionfield reaches its maximum value, its value shall wraparound to 0.

‘atsc3_message_content_compression’—An 8-bit unsigned integer field thatshall identify the type of compression applied to the data inatsc3_message_content_byte.

‘URI length’—An 8-bit unsigned integer field that shall provide thelength of the Universal Resource Identifier (URI) uniquely identifyingthe message payload across services. If the URI is not present, thevalue of this field shall be set to 0.

‘URI byte’—An 8-bit unsigned integer field that shall contain a UTF-8[where UTF is an acronym of unicode transformation format] character ofthe URI associated with the content carried by this message excludingthe terminating null character, as per Internet Engineering Task Force(IETF) Request for Comments (RFC) 3986. This field when present shall beused to identify delivered message payloads. The URI can be used bysystem tables to reference tables made available by delivered messagepayloads.

‘atsc3_message_content_length’—A 32-bit unsigned integer field thatshall provide the length of the content carried by this message.

‘atsc3_message_content_byte’—An 8-bit unsigned integer field that shallcontain a byte of the content carried by this message.

It should be noted that with respect to Table 3 and Table 4 that A/331defines a video stream properties descriptor, but does not currentlydefine an audio stream properties descriptor. Audio stream propertiesdescriptors are currently being proposed. For example, it has beenproposed to expand atsc3 message content type as follows:

‘atsc3_message_content_type’—A 16-bit unsigned integer field that shalluniquely identify the type of message content in the mmt atsc3_message() payload, coded per Table [5] below.

TABLE 5 atsc3_message_content_type Meaning 0x0000 Reserved 0x0001 A UserService Bundle Description Fragment for MMT 0x0002 An Media PresentationDescriptor (MPD) 0x0003 An Application Information Table 0x0004Application Event Information 0x0005 Video Stream Properties Descriptor0x0006 An ATSC Staggercast Descriptor 0x0007 An Inband Event Descriptor0x0008 Caption Asset Descriptor 0x0009 Audio Stream PropertiesDescriptor 0x0010~0xFFFF Reserved for future use

With respect to Table 5, it should be noted that other values‘atsc3_message_content_type’ may correspond to Audio Stream PropertiesDescriptor (e.g., any of 0x0010-0xFFFF).

Referring again to FIG. 2, for service layer signaling with respect to aROUTE/DASH delivery mechanism, A/331 service layer signaling includes aService-based Transport Session Instance Description (S-TSID), a UserService Bundle Descriptor (USBD), and a Media Presentation Document(MPD). Each of a S-TSID, a USBD, and a MPD may include fragments thatdescribe service layer properties. A fragment may include a set ofXML-encoded metadata fragments. In one example, the metadata fragmentsmay be carried over a dedicated LCT channel. In A/331, the USBD fragmentincludes service identification, device capabilities information,references to other SLS fragments required to access the service andconstituent media components, and metadata to enable the receiver todetermine the transport mode (e.g., broadcast and/or broadband) ofservice components. In A/331, the USBD also includes a reference to anMPD fragment that contains descriptions for content components of theATSC 3.0 Service delivered over broadcast and/or broadband. In A/331,the USBD also includes a reference to the S-TSID fragment which providesaccess related parameters to the transport sessions carrying contents ofthis ATSC 3.0 Service. In A/331, the S-TSID fragment, referenced by theUSBD, provides transport session descriptions for the one or more ROUTEsessions in which the media content components of a service aredelivered, and descriptions of the delivery objects carried in those LCTchannels. For the sake of brevity, details of the format of the S-TSIDand the USBD fragments are not described herein, however, reference ismade to A/331.

In A/331, the MPD is a SLS metadata fragment that includes a formalizeddescription of a DASH-IF (DASH Interoperability Forum) profile of a DASHMedia Presentation. A DASH Media Presentation may correspond to a linearservice or part of a linear service of a given duration defined by aservice provider (e.g., a single TV program, or the set of contiguouslinear TV programs over a period of time). The contents of the MPDprovide the resource identifiers for segments and the context for theidentified resources within the Media Presentation. In A/331, the datastructure and semantics of the MPD fragment are described with respectto the Media Presentation Description as defined by the DASH-IF profileof MPEG DASH ISO/IEC: ISO/IEC 23009-1:2014, “Informationtechnology—Dynamic adaptive streaming over HTTP (DASH)—Part 1: Mediapresentation description and segment formats,” InternationalOrganization for Standardization, 2nd Edition, May 15, 2014(hereinafter, “ISO/IEC 23009-1:2014”), which is incorporated byreference herein. It should be noted that draft third editions ofISO/IEC 23009-1 are currently being proposed. Thus, a MPD may include aMPD as described in “ISO/IEC 23009-1:2014,” currently proposed MPDs,and/or combinations thereof.

A Media Presentation as described in a MPD may include a sequence of oneor more Periods, where each Period may include one or more AdaptationSets. It should be noted that in the case where an Adaptation Setincludes multiple media content components, then each media contentcomponent may be described individually. Each Adaptation Set may includeone or more Representations. The properties of each media contentcomponent may be described by an AdaptationSet element and/or elementswithin an Adaption Set, including for example, a ContentComponentelement. An audio presentation, which in some examples may be referredto as a preselection may include a set of audio components (e.g.,dialog, music, effects, etc.). In ISO/IEC JTC1/SC29/WG11MPEG2015/M37918, February 2016, San Diego, Calif., US, which isincorporated by reference herein, it has been proposed to signalinformation associated with a preselection according to the examplesemantics illustrated in Table 4.5.

TABLE 4.5 Element or Attribute Name Use Description Preselection @id ODspecifies the id of the Preselection. This Default = 1 shall be uniquewithin one bundle. @audioSamplingRate O Either a single decimal integervalue specifying the sampling rate or a whitespace separated pair ofdecimal integer values specifying the minimum and maximum sampling rateof the audio media component type. The values are in samples per second.If not present on any level, the value is unknown. @codecs O specifiesthe codecs required to decode the Representation. The codec parametersshall also include the profile and level information where applicable.@selectionPriority OD @preselectionComponents 1 The list of ids ofContent Components which are necessary to present the Preselection.Language 0 . . . N declares a language code for this Preselection. Ifnot present, the language code may be defined for each media componentor it may be unknown. Role 0 . . . N Describes the Role of thePreselection Accessibility 0 . . . N Describes the accessibilityfeatures of the preselection Label 0 . . . N Text labelAudioChannelConfiguration 0 . . . N specifies the audio channelconfiguration of the audio media component type. EssentialProperty 0 . .. N specifies information about the containing element that isconsidered essential by the Media Presentation author for processing thecontaining element. SupplementalProperty 0 . . . N specifiessupplemental information about the containing element that may be usedby the DASH client optimizing the processing. AudioRenderingInformation0 . . . N specifies properties that are relevant for audio rendering.ContentInteractivity 0 . . . N specifies properties on the contentinteractivity of this pre-selection. Legend: For attributes: M =Mandatory, O = Optional, OD = Optional with Default Value, CM =Conditionally Mandatory. For elements: <minOccurs> . . . <maxOccurs> (N= unbounded) Elements are bold; attributes are non-bold and precededwith an @.

As described above, a service (e.g., a linear audio/video service) mayinclude an emergency information audio component. For example, in somecases, audio streams may include audio content associated with anemergency information displayed during the rendering of a video service(e.g., a redistribution of a video including a scrolling alert message).Further, as described above, in A/331, an emergency alert service mayprovide emergency alert information and may include text and associatedvideo and/or audio content. Thus, audio streams may include audiocontent associated with emergency information where emergencyinformation may be provided through one or more types of services. Inthe case of visually impaired users, it may be beneficial and/ornecessary to include an audio presentation of emergency information inorder for visually impaired users to auditorily/aurally discern theemergency information. Currently proposed audio stream propertydescriptors fail to provide information indicating whether an audiostream includes audio content associated with an emergency and furtherfail to provide information associated with audio content associatedwith emergency information. Failing to provide information indicatingwhether an audio stream includes audio content associated with anemergency and failing to provide information associated with audiocontent associated with an emergency may be less than ideal.

As described above, a service (e.g., a linear audio/video service) mayinclude an audio program (which be referred to as a bundle or an audioscene) which may include a set of audio program components that may beused to form one or more audio presentations. Each audio presentationmay be associated with one or more languages. For example, apresentation may include an English language director's commentary and aSpanish Language dialogue or video description. Further, a presentationmay support one or more types of accessibility, e.g., visually impairedand/or hearing impaired accessibility. Currently proposed audio streamproperties descriptors for the ATSC 3.0 suite of standards are less thanideal with respect to signaling language and accessibility informationfor a presentation.

FIG. 3 is a block diagram illustrating an example of a system that mayimplement one or more techniques described in this disclosure. System300 may be configured to communicate data in accordance with thetechniques described herein. In the example illustrated in FIG. 3,system 300 includes one or more receiver devices 302A-302N, televisionservice network 304, television service provider site 306, wide areanetwork 312, one or more content provider sites 314A-314N, and one ormore data provider sites 316A-316N. System 300 may include softwaremodules. Software modules may be stored in a memory and executed by aprocessor. System 300 may include one or more processors and a pluralityof internal and/or external memory devices. Examples of memory devicesinclude file servers, file transfer protocol (FTP) servers, networkattached storage (NAS) devices, local disk drives, or any other type ofdevice or storage medium capable of storing data. Storage media mayinclude Blu-ray discs, DVDs, CD-ROMs, magnetic disks, flash memory, orany other suitable digital storage media. When the techniques describedherein are implemented partially in software, a device may storeinstructions for the software in a suitable, non-transitorycomputer-readable medium and execute the instructions in hardware usingone or more processors.

System 300 represents an example of a system that may be configured toallow digital media content, such as, for example, a movie, a livesporting event, etc., and data and applications and media presentationsassociated therewith, to be distributed to and accessed by a pluralityof computing devices, such as receiver devices 302A-302N. In the exampleillustrated in FIG. 3, receiver devices 302A-302N may include any deviceconfigured to receive data from television service provider site 306.For example, receiver devices 302A-302N may be equipped for wired and/orwireless communications and may include televisions, including so-calledsmart televisions, set top boxes, and digital video recorders. Further,receiver devices 302A-302N may include desktop, laptop, or tabletcomputers, gaming consoles, mobile devices, including, for example,“smart” phones, cellular telephones, and personal gaming devicesconfigured to receive data from television service provider site 306. Itshould be noted that although system 300 is illustrated as havingdistinct sites, such an illustration is for descriptive purposes anddoes not limit system 300 to a particular physical architecture.Functions of system 300 and sites included therein may be realized usingany combination of hardware, firmware and/or software implementations.

Television service network 304 is an example of a network configured toenable digital media content, which may include television services, tobe distributed. For example, television service network 304 may includepublic over-the-air television networks, public or subscription-basedsatellite television service provider networks, and public orsubscription-based cable television provider networks and/or over thetop or Internet service providers. It should be noted that although insome examples television service network 304 may primarily be used toenable television services to be provided, television service network304 may also enable other types of data and services to be providedaccording to any combination of the telecommunication protocolsdescribed herein. Further, it should be noted that in some examples,television service network 304 may enable two-way communications betweentelevision service provider site 306 and one or more of receiver devices302A-302N. Television service network 304 may comprise any combinationof wireless and/or wired communication media. Television service network304 may include coaxial cables, fiber optic cables, twisted pair cables,wireless transmitters and receivers, routers, switches, repeaters, basestations, or any other equipment that may be useful to facilitatecommunications between various devices and sites. Television servicenetwork 304 may operate according to a combination of one or moretelecommunication protocols. Telecommunications protocols may includeproprietary aspects and/or may include standardized telecommunicationprotocols. Examples of standardized telecommunications protocols includeDVB standards, ATSC standards, ISDB standards, DTMB standards, DMBstandards, Data Over Cable Service Interface Specification (DOCSIS)standards, HbbTV standards, W3C standards, and UPnP standards.

Referring again to FIG. 3, television service provider site 306 may beconfigured to distribute television service via television servicenetwork 304. For example, television service provider site 306 mayinclude one or more broadcast stations, a cable television provider, ora satellite television provider, or an Internet-based televisionprovider. In the example illustrated in FIG. 3, television serviceprovider site 306 includes service distribution engine 308 and database310. Service distribution engine 308 may be configured to receive data,including, for example, multimedia content, interactive applications,and messages, including emergency alert messages, and distribute data toreceiver devices 302A-302N through television service network 304. Forexample, service distribution engine 308 may be configured to transmittelevision services according to aspects of the one or more of thetransmission standards described above (e.g., an ATSC standard). In oneexample, service distribution engine 308 may be configured to receivedata through one or more sources. For example, television serviceprovider site 306 may be configured to receive a transmission includingtelevision programming through a satellite uplink/downlink Further, asillustrated in FIG. 3, television service provider site 306 may be incommunication with wide area network 312 and may be configured toreceive data from content provider sites 314A-314N and further receivedata from data provider sites 316A-316N. It should be noted that in someexamples, television service provider site 306 may include a televisionstudio and content may originate therefrom.

Database 310 may include storage devices configured to store dataincluding, for example, multimedia content and data associatedtherewith, including for example, descriptive data and executableinteractive applications. For example, a sporting event may beassociated with an interactive application that provides statisticalupdates. Data associated with multimedia content may be formattedaccording to a defined data format, such as, for example, HypertextMarkup Language (HTML), Dynamic HTML, eXtensible Markup Language (XML),and JavaScript Object Notation (JSON), and may include UniversalResource Locators (URLs) and Universal Resource Identifiers (URIs)enabling receiver devices 302A-302N to access data, e.g., from one ofdata provider sites 316A-316N. In some examples, television serviceprovider site 306 may be configured to provide access to storedmultimedia content and distribute multimedia content to one or more ofreceiver devices 302A-302N through television service network 304. Forexample, multimedia content (e.g., music, movies, and television (TV)shows) stored in database 310 may be provided to a user via televisionservice network 304 on a so-called on demand basis.

Wide area network 312 may include a packet based network and operateaccording to a combination of one or more telecommunication protocols.Telecommunications protocols may include proprietary aspects and/or mayinclude standardized telecommunication protocols. Examples ofstandardized telecommunications protocols include Global System MobileCommunications (GSM) standards, code division multiple access (CDMA)standards, 3rd Generation Partnership Project (3GPP) standards, EuropeanTelecommunications Standards Institute (ETSI) standards, Europeanstandards (EN), IP standards, Wireless Application Protocol (WAP)standards, and Institute of Electrical and Electronics Engineers (IEEE)standards, such as, for example, one or more of the IEEE 802 standards(e.g., Wi-Fi). Wide area network 312 may comprise any combination ofwireless and/or wired communication media. Wide area network 312 mayinclude coaxial cables, fiber optic cables, twisted pair cables,Ethernet cables, wireless transmitters and receivers, routers, switches,repeaters, base stations, or any other equipment that may be useful tofacilitate communications between various devices and sites. In oneexample, wide area network 316 may include the Internet.

Referring again to FIG. 3, content provider sites 314A-314N representexamples of sites that may provide multimedia content to televisionservice provider site 306 and/or receiver devices 302A-302N. Forexample, a content provider site may include a studio having one or morestudio content servers configured to provide multimedia files and/orstreams to television service provider site 306. In one example, contentprovider sites 314A-314N may be configured to provide multimedia contentusing the IP suite. For example, a content provider site may beconfigured to provide multimedia content to a receiver device accordingto Real Time Streaming Protocol (RTSP), HTTP, or the like.

Data provider sites 316A-316N may be configured to provide data,including hypertext based content, and the like, to one or more ofreceiver devices 302A-302N and/or television service provider site 306through wide area network 312. A data provider site 316A-316N mayinclude one or more web servers. Data provided by data provider site316A-316N may be defined according to data formats, such as, forexample, HTML, Dynamic HTML, XML, and JSON. An example of a dataprovider site includes the United States Patent and Trademark Officewebsite. It should be noted that in some examples, data provided by dataprovider sites 316A-316N may be utilized for so-called second screenapplications. For example, companion device(s) in communication with areceiver device may display a website in conjunction with televisionprogramming being presented on the receiver device. It should be notedthat data provided by data provider sites 316A-316N may include audioand video content.

As described above, service distribution engine 308 may be configured toreceive data, including, for example, multimedia content, interactiveapplications, and messages, and distribute data to receiver devices302A-302N through television service network 304. FIG. 4 is a blockdiagram illustrating an example of a service distribution engine thatmay implement one or more techniques of this disclosure. Servicedistribution engine 400 may be configured to receive data and output asignal representing that data for distribution over a communicationnetwork, e.g., television service network 304. For example, servicedistribution engine 400 may be configured to receive one or more datastreams and output a signal that may be transmitted using a single radiofrequency band (e.g., a 6 MHz channel, an 8 MHz channel, etc.) or abonded channel (e.g., two separate 6 MHz channels). A data stream maygenerally refer to data encapsulated in a set of one or more datapackets.

As illustrated in FIG. 4, service distribution engine 400 includescomponent encapsulator 402, transport/network packet generator 404, linklayer packet generator 406, frame builder and waveform generator 408,and system memory 410. Each of component encapsulator 402,transport/network packet generator 404, link layer packet generator 406,frame builder and waveform generator 408, and system memory 410 may beinterconnected (physically, communicatively, and/or operatively) forintercomponent communications and may be implemented as any of a varietyof suitable circuitry, such as one or more microprocessors, digitalsignal processors (DSPs), application specific integrated circuits(ASICs), field programmable gate arrays (FPGAs), discrete logic,software, hardware, firmware or any combinations thereof. It should benoted that although service distribution engine 400 is illustrated ashaving distinct functional blocks, such an illustration is fordescriptive purposes and does not limit service distribution engine 400to a particular hardware architecture. Functions of service distributionengine 400 may be realized using any combination of hardware, firmwareand/or software implementations.

System memory 410 may be described as a non-transitory or tangiblecomputer-readable storage medium. In some examples, system memory 410may provide temporary and/or long-term storage. In some examples, systemmemory 410 or portions thereof may be described as non-volatile memoryand in other examples portions of system memory 410 may be described asvolatile memory. Examples of volatile memories include random accessmemories (RAM), dynamic random access memories (DRAM), and static randomaccess memories (SRAM). Examples of non-volatile memories includemagnetic hard discs, optical discs, floppy discs, flash memories, orforms of electrically programmable memories (EPROM) or electricallyerasable and programmable (EEPROM) memories. System memory 410 may beconfigured to store information that may be used by service distributionengine 400 during operation. It should be noted that system memory 410may include individual memory elements included within each of componentencapsulator 402, transport/network packet generator 404, link layerpacket generator 406, and frame builder and waveform generator 408. Forexample, system memory 410 may include one or more buffers (e.g.,First-in First-out (FIFO) buffers) configured to store data forprocessing by a component of service distribution engine 400.

Component encapsulator 402 may be configured to receive one or morecomponents of a service and encapsulate the one or more componentsaccording to a defined data structure. For example, componentencapsulator 402 may be configured to receive one or more mediacomponents and generate a package based on MMTP. Further, componentencapsulator 402 may be configured to receive one or more mediacomponents and generate media presentation based on DASH. It should benoted that in some examples, component encapsulator 402 may beconfigured to generate service layer signaling data. Transport/networkpacket generator 404 may be configured to receive a transport packageand encapsulate the transport package into corresponding transport layerpackets (e.g., UDP, Transport Control Protocol (TCP), etc.) and networklayer packets (e.g., Ipv4, Ipv6, compressed IP packets, etc.). Linklayer packet generator 406 may be configured to receive network packetsand generate packets according to a defined link layer packet structure(e.g., an ATSC 3.0 link layer packet structure).

Frame builder and waveform generator 408 may be configured to receiveone or more link layer packets and output symbols (e.g., OFDM symbols)arranged in a frame structure. As described above, a frame may includeone or more PLPs may be referred to as a physical layer frame (PHY-Layerframe). In one example, a frame structure may include a bootstrap, apreamble, and a data payload including one or more PLPs. A bootstrap mayact as a universal entry point for a waveform. A preamble may includeso-called Layer-1 signaling (L1-signaling). L1-signaling may provide thenecessary information to configure physical layer parameters. Framebuilder and waveform generator 408 may be configured to produce a signalfor transmission within one or more of types of RF channels: a single 6MHz channel, a single 7 MHz channel, single 8 MHz channel, a single 11MHz channel, and bonded channels including any two or more separatesingle channels (e.g., a 14 MHz channel including a 6 MHz channel and a8 MHz channel). Frame builder and waveform generator 408 may beconfigured to insert pilots and reserved tones for channel estimationand/or synchronization. In one example, pilots and reserved tones may bedefined according to an OFDM symbol and sub-carrier frequency map. Framebuilder and waveform generator 408 may be configured to generate an OFDMwaveform by mapping OFDM symbols to sub-carriers. It should be notedthat in some examples, frame builder and waveform generator 408 may beconfigured to support layer division multiplexing. Layer divisionmultiplexing may refer to super-imposing multiple layers of data on thesame RF channel (e.g., a 6 MHz channel). Typically, an upper layerrefers to a core (e.g., more robust) layer supporting a primary serviceand a lower layer refers to a high data rate layer supporting enhancedservices. For example, an upper layer could support basic HighDefinition video content and a lower layer could support enhancedUltra-High Definition video content.

As described above, component encapsulator 402 may be configured toreceive one or more media components and generate a package based onMMTP. FIG. 5A is a block diagram illustrating an example of a componentencapsulator that may implement one or more techniques of thisdisclosure. Component encapsulator 500 may be configured to generate apackage according to the techniques described herein. In the exampleillustrated in FIG. 5A, functional blocks of component encapsulator 500correspond to functional blocks for generating a package (e.g., an MMTPackage). As illustrated in FIG. 5A, component encapsulator 500 includespresentation information generator 502, asset generator 504, and assetdelivery characteristic generator 506. Each of presentation informationgenerator 502, asset generator 504, and asset delivery characteristicgenerator 506 may be interconnected (physically, communicatively, and/oroperatively) for inter-component communications and may be implementedas any of a variety of suitable circuitry, such as one or moremicroprocessors, digital signal processors (DSPs), application specificintegrated circuits (ASICs), field programmable gate arrays (FPGAs),discrete logic, software, hardware, firmware or any combinationsthereof. It should be noted that although component encapsulator 500 isillustrated as having distinct functional blocks, such an illustrationis for descriptive purposes and does not limit component encapsulator500 to a particular hardware architecture. Functions of componentencapsulator 500 may be realized using any combination of hardware,firmware and/or software implementations.

Asset generator 504 may be configured to receive media components andgenerate one or more assets for inclusion in a package. Asset deliverycharacteristic generator 506 may be configured to receive informationregarding assets to be included in a package and provide QoSrequirements. Presentation information generator 502 may be configuredto generate presentation information documents. As described above, aMMT package includes presentation information (PI) and asset deliverycharacteristics (ADC) and a PI document may be delivered as one or moresignalling messages. Thus, presentation information generator 502 may beconfigured to generate signalling messages according to the techniquesdescribed herein. It should be noted that in some examples, a servicedistribution engine (e.g., service distribution engine 308 or servicedistribution engine 400) or specific components thereof may beconfigured to generate signalling messages according to the techniquesdescribed herein. As such, description of signalling messages withrespect to presentation information generator 502 should not beconstrued to limit the techniques described herein.

As described above, with respect to Table 2 and Table 3, A/331 does notcurrently define an audio stream properties descriptor and currentlyproposed audio stream properties descriptor are less than ideal withrespect indicating whether an audio stream includes audio contentassociated with an emergency alert and fail to provide informationassociated with audio content associated with an emergency alert. Table5A and Table 5B provide examples of syntax of anaudio_stream_properties_descriptor( ) message. Table 5A and Table 5Brepresent general examples of an audio_stream_properties_descriptor( )message including information indicating an audio stream includes audiocontent associated with an emergency alert. As describe in furtherdetail below, in some examples, in additional to including informationindicating an audio stream includes audio content associated with anemergency alert, an audio_stream_properties_descriptor( ) may includeadditional syntax elements, i.e., ‘[Additional audio stream propertyinformation]’ in Table 5A and Table 5B may be associated with additionalsyntax elements indicating audio stream property information. Further,it should be noted that Table 5A and Table 5B include examples whereemergency_information_time_info( ) structure may be included in one ormore levels of syntax. For example, an audio presentation, which in someexamples may be referred to as a preselection may include a set of audiocomponents (e.g., dialog, music, effects, etc.),emergency_information_time_info( ) structure may be signaled at thepresentation level and/or at the component level.

TABLE 5A No. of Syntax Bits Format audio_stream_properties_descriptor( ){   descriptor_tag 16 uimsbf   descriptor_length 16 uimsbf   ...  [Additional audio stream property information]   ...  If(emergency_information_present) {  emergency_information_start_time_present  emergency_information_end_time_present   If(emergency_information_start_time_present)   {    emergency_information_start_time 32 uimsbf     reserved 6 ‘11 1111’    emergency_information_start_time_ms 10 uimsbf   }   If(emergency_information_end_time_present)   {    emergency_information_end_time 32 uimsbf     reserved 6 ‘11 1111’    emergency_information_end_time_ms 10 uimsbf   } //emergency_information_time_info( )   structure }

TABLE 5B No. of Syntax Bits Format audio_stream_properties_descriptor( ){   descriptor_tag 16 uimsbf   descriptor_length 16 uimsbf   ...  [Additional audio stream property information]   ...  If(emergency_information_present) {  emergency_information_start_time_present 1 bslbf  emergency_information_end_time_present 1 bslbf   reserved 6 ‘11 1111’  If (emergency_information_start_time_present)   {   emergency_information_start_time 32 uimsbf    reserved 6 ‘11 1111’   emergency_information_start_time_ms 10 uimsbf   }   If(emergency_information_end_time_present)   {   emergency_information_end_time 32 uimsbf    reserved 6 ‘11 1111’   emergeney_information_end_time_ms 10 uimsbf    } //emergency_information_time_Info( )    structure }

In the examples illustrated in Table 5A and Table 5B, syntax elements‘descriptor_tag’, ‘descriptor_length’,‘emergency_information_start_time_present’,‘emergency_information_end_time_present’,‘emergency_information_start_time’,‘emergency_information_start_time_ms’, ‘emergency_information_end_time’and ‘emergency_information_end_time_ms’ may be based on the followingexample definitions:

‘descriptor_tag’—This 16-bit unsigned integer shall have the value0x0009 [or any of 0x0009-0xFFFF], identifying this descriptor as beingthe audio_stream_properties_descriptor( ).

‘descriptor_length’—This 16-bit unsigned integer shall specify thelength (in bytes) immediately following this field up to the end of thisdescriptor.

‘emergency_information_start_time_present’—This one-bit Boolean flagshall indicate, when set to ‘1’, that the fields“emergency_information_start_time” and“emergency_information_start_time_ms” are present. When set to ‘0’, thefields “emergency_information_start_time” and“emergency_information_start_time_ms” shall not be present.

‘emergency_information_end_time_present’—This one-bit Boolean flag shallindicate, when set to ‘1’, that the fields“emergency_information_end_time” and “emergency_information_end_time_ms”are present. When set to ‘0’, the fields“emergency_information_end_time” and “emergency_information_end_time_ms”shall not be present.

‘emergency_information_start_time’—This 32-bit unsigned integer shallindicate the start time of the aural/audio representation of theemergency information, as the least-significant 32 bits of the count ofthe number of seconds since Jan. 1, 1970 00:00:00, International AtomicTime (TAI).

‘emergency_information_start_time_ms’—This 10-bit unsigned integer inthe range 0 to 999 shall indicate the milliseconds offset from the timeindicated in emergency_information_start_time, such that the formulaemergency_information_start_time+(emergency_information_start_time_ms/1000)yields the start time of the audio/aural emergency information to thenearest 1 millisecond.

‘emergency_information_end_time’—This 32-bit unsigned integer shallindicate the end time of the aural/audio representation of the emergencyinformation, as the least-significant 32 bits of the count of the numberof seconds since Jan. 1, 1970 00:00:00, International Atomic Time (TAI).

‘emergency_information_end_time_ms’—This 10-bit unsigned integer in therange 0 to 999 shall indicate the milliseconds offset from the timeindicated in emergency_information_end_time, such that the formulaemergency_information_end_time+(emergency_information_end_time_ms/1000)yields the end time of the audio/aural emergency information to thenearest 1 millisecond.

It should be noted that in some examples, the values of‘emergency_information_start_time_present’ and/or‘emergency_information_end_time_present’ may be inferred. For example,in one example each of ‘emergency_information_start_time_present’ and/or‘emergency_information_end_time_present’ may not be signalled andinfered to be zero. For example, the values may be inferred fromsignalling occuring at another level. For example, a syntax may be usedwhere for syntax elements that are not included their value is inferredto be zero. In one example, ‘emergency_information_start_time_present’and ‘emergency_information_end_time_present’ may be based on thefollowing definitions:

‘emergency_information_start_time_present’—This one-bit Boolean flagshall indicate, when set to ‘1’, that the fields“emergency_information_start_time” and“emergency_information_start_time_ms” are present. When set to ‘0’, thefields “emergency_information_start_time” and“emergency_information_start_time_ms” shall not be present and the starttime of the aural/audio representation of the emergency informationshall be inferred to be equal to the presentation time of first mediasample in presentation order in the audio asset, [where sample includesan ISOBMFF (ISO Base Media File Format) sample and is defined as: allthe data associated with a single timestamp].

‘emergency_information_end_time_present’—This one-bit Boolean flag shallindicate, when set to ‘1’, that the fields“emergency_information_end_time” and “emergency_information_end_time_ms”are present. When set to ‘0’, the fields“emergency_information_end_time” and “emergency_information_end_time_ms”shall not be present and the end time of the aural/audio representationof the emergency information shall be inferred to be equal to thepresentation time of the last media sample in presentation order in theaudio asset, [where sample includes an ISOBMFF sample].

It should be noted that information signaled usingemergency_information_time_info( ) structure may be particularly usefulfor enabling splicing and processing (e.g. mixing, replacement) ofaudio/aural representation of emergency information at one or morelocations in system 300. It should be noted that in other examples,other formats may be used to signal time values e.g., a 64-bit NetworkTime Protocol (NTP) timestamp value, etc.

It should be noted that with respect to Table 5A and Table 5B, thecondition “If (emergency_information_present)” may be determined basedon one or more syntax elements included in anaudio_stream_properties_descriptor( ), for example, in one example, anaudio_stream_properties_descriptor( ) may include a syntax element‘emergency_information_present_flag’, where‘emergency_information_present_flag’ is based on the following exampledefinition:

‘emergency_information_present_flag’—A 1-bit flag, when set to ‘1’indicates that the audio asset contains an audio/aural representation ofemergency information and that the elements in theemergency_information_time_info( ) structure are present. When set to‘0’ indicates that the audio asset does not contain an audio/auralrepresentation of emergency information and that the elements in theemergency_information_time_info( ) structure are not present.

In one example, an audio_stream_properties_descriptor( ) may include apreselection information. Table 6 provides an example ofpreselection_info( ).

TABLE 6 No. of Syntax Bits Format preselection_info( ) {num_preselections 7 uimsbf reserved 1 ‘1’ for(k=0; k< num_preselections;k++) { preselection_id 7 uimbsf label_present 1 bslbfprimary_language_length 8 uimbsf for (j=0; j<language_length; j++) {primary_language_byte 8 uimsbf } accessibility 8 uimsbf role 8 uimsbf if(label_present) { label_length 8 uimsbf for(l=0; 1< label_length; 1++) {label_data_byte 8 uimbsf } } emergency_information_present_flag 1 bslbfreserved 7 ‘111 1111’ } }

In the example illustrated in Table 6, syntax elements‘num_preselections’, ‘preselection_ID’, ‘label_present’,‘primary_language_length’, ‘primary_language’, ‘accessibility’, ‘role’,‘label_length’, ‘label_data_byte’, and‘emergency_information_present_flag’ may be based on the followingexample definitions:

‘num_preselections’—This 7-bit unsigned integer field shall indicate thenumber of Preselections that are available within the main stream andall auxiliary streams.

‘preselection_ID’—This 7-bit unsigned integer field shall identify theID of this Preselection.

‘label_present’—This 1-bit Boolean flag shall indicate, when set to ‘1’,that a text label for this Preselection is present. When set to ‘0’,this flag shall indicate that the text label for this Preselection isnot present.

‘primary_language_length’—An 8-bit unsigned integer field that shallspecify the length in bytes of the primary language supported in thePreselection.

‘primary_language_byte’—An 8-bit unsigned integer field that shallcontain a UTF-8 character of the language of the primary audio dialoguecomponent in this Preselection. The primary language of the Preselectionshall be given by a language tag as defined by IETF BCP 47 [InternetEngineering Task Force (IETF) Best Current Practice (BCP) 47 publishedSeptember 2009], where a UTF-8 character may be defined based on thefollowing definition: UTF-8 is a character encoding capable of encodingall possible characters, or code points, in Unicode. The encoding isvariable-length and uses 8-bit code units. The name is derived from:Universal Coded Character Set+Transformation Format-8-bit.

‘accessibility’—This 8-bit unsigned integer field shall identify theaccessibility support for this Preselection. Accessibility support issignaled for the primary language in this Preselection. If the streamcontains audio components for accessibility support, this is signaledwith the following values for this field: 0=no accessibility support,1=Visually Impaired, 2=Hearing Impaired, 3=Visually and HearingImpaired, 255=unknown. The values 4 to 254 are reserved.

‘role’—This 8-bit unsigned integer field shall indicate the role of thePreselection.

‘label_length’—This 8-bit unsigned integer field shall specify thelength in bytes of this Preselection text label.

‘label_data_byte’—An 8-bit unsigned integer field that shall contain abyte of the Preselection text label.

‘emergency_information_present_flag’—A 1-bit flag, when set to ‘1’indicates that the Preselection contains an audio/aural representationof emergency information. When set to ‘0’ indicates that thePreselection does not contain an audio/aural representation of emergencyinformation.

It should be noted that in some examples,‘emergency_information_present_flag’ in Table 6 may indicate whether theelements in the emergency_information_time_info( ) structure arepresent. It should be noted that in one example, syntax element ‘role’may indicate a role based on the code values provided in Table 7A and inone example may indicate a role based on the code values provided inTable 7B.

TABLE 7A role Meaning 0x00 main 0x01 alternate 0x02 commentary 0x03video description 0x04 emergency information 0x05~0xFF reserved forfuture use

TABLE 7B role Meaning 0x00 Main - complete main 0x01 Main - music andeffects 0x02 alternate 0x03 commentary 0x04 video description 0x05emergency information 0x06~0xFF reserved for future use

As illustrated in Table 7A and Table 7B syntax element ‘role’ may beused to indicate that an audio stream corresponds to emergencyinformation. Thus, in some examples the condition “If(emergency_information_present)” in Table 5 may be determined based on avalue of ‘role’. Further, it should be noted that in some examplessyntax element ‘role’ may be present inaudio_stream_properties_descriptor( ) in syntax other thanpreselection_info( ) e.g., in the line before, “If(emergency_information_present)” condition in Table 5. Further, itshould be noted that in some examples, values of syntax element‘accessibility’ may be used to determine the “If(emergency_information_present)” condition. It should be noted that insome examples, syntax element ‘role’ may indicate a role based on thecode values provided in Table 7C.

TABLE 7C role Meaning 0x00 Main - complete main 0x01 Main - music andeffects 0x02 alternate 0x03 commentary 0x04 video description 0x05~0xFFreserved for future use

As described above, ‘[Additional audio stream property information]’ inTable 5 may may be associated with additional syntax elements indicatingaudio stream property information. Table 8A provides an example of anaudio_stream_properties_descriptor( ) including additional syntaxelements.

TABLE 8A No. of Syntax Bits Format audio_stream_properties_descriptor( ){ descriptor_tag 16 uimsbf descriptor_length 16 uimsbf number_of_assets8 uimsbf for (i=0;i<number_of_assets;i++) { asset_id_length 8 uimsbf for(j=0; j<asset_id_length; j++) { asset_id_byte 8 uimsbf } codec_code 4*8uimsbf profile_level_indication 8 uimsbf audio_channel_configuration 6uimsbf interactivity_enabled 1 bslbf reserved 1 ‘1’ if(audio_channel_configuration == 0) { channel_layout_indication 2 uimsbfreference_channel_layout 6 uimsbf } preselection_info_present 1 bslbfmulti-stream_info_present 1 bslbf reserved 6 ‘111111’ if(preselection_info_present) { preselection_info( ) Table 6 } if(multi-stream_info_present) { multi-stream_info( ) Table 10 }primary_language_length 8 uimbsf for (k=0; k<language_length; k++) {primary_language_byte 8 uimsbf } accessibility 8 uimbsfnum_additional_languages 8 uimbsf for(l=0; l< num_additional_languages;l++) { additional_language_length 8 uimbsf for (m=0; m<language_length;m++) { additional_language_byte 8 uimsbf } accessibility 8 uimbsf }emergency_information_present_flag 1 bslbf reserved 7 ‘111 1111’emergency_information_time_ info( ) Table 5 A or Table 5B  } }

In the example illustrated in Table 8A, syntax elements ‘descriptor_tag’and ‘descriptor_length’, and ‘emergency_information_present_flag’ may bebased on the definitions provided above. Syntax elements‘number_of_assets’, ‘asset_id_length’, ‘asset_id_byte’, ‘codec_code’,‘profile_level_indication’, ‘audio_channel_configuration’,‘channel_layout_indication’, ‘reference_channel_layout’,‘interactivity_enabled’, ‘preselection_info_present’,‘multi_stream_info_present’, ‘primary_language_length’,‘primary_language_byte’, ‘num_additional_languages’,‘additional_language_length’, ‘additional_language_byte’,‘accessibility’, and ‘emergency_information_present_flag’ may be basedon the following example definitions: ‘number_of_assets’—An 8-bitunsigned integer field that shall specify the number of audio assetsdescribed by this descriptor.

‘asset_id_length’—This 8-bit unsigned integer field shall specify thelength in bytes of the audio asset id.

‘asset_id_byte’—An 8-bit unsigned integer field that shall contain abyte of the audio asset id.

‘codec_code’—This 32-bit unsigned integer field shall specify a4-character code for a codec.

‘profile_level_indication’—This 8-bit unsigned integer field shallindicate the audio profile and level of the associated audio stream.

‘audio_channel_configuration’—This 6-bit unsigned integer field shallindicate the audio channel configuration of the encoded audio stream. Ifthis field is ‘0’, the encoded audio may contain a combination of audioelements that are not channel-based, e.g. audio objects, so that asingle audio channel configuration value is not meaningful.

It should be noted that in some examples, for audio channelconfigurations there may be one or more corresponding schemes. In thismanner, in some examples a corresponding syntax element indicating ascheme may be signaled.

‘channel_layout_indication’—This 2-bit unsigned integer field maycontain a hint for a preferred reproduction channel layout, ifaudio_channel_configuration is set to ‘0’. Values ofchannel_layout_indication shall be as specified in Table 9. Note thatthe following field reference_channel_layout may be used to signal aspecific preferred reproduction channel layout.

TABLE 9 channel_layout_indication value Meaning ‘00’ There is nopreference given for the reproduction channel layout. ‘01’ The contentis pre-rendered for consumption with headphones. In this case, thefollowing field reference_channel_layout shall be set to ‘0’. ‘10’ Thecontent has only elements to be rendered in a plane, i.e. the preferredreproduction channel layout is a two-dimensional layout ‘11’ the contenthas elements with heights, i.e. the preferred reproduction channellayout is a three-dimensional layout

‘reference_channel_layout’—For values other than ‘0’, this 6-bitunsigned integer field shall identify the reference channelconfiguration that describes the loudspeaker layout for which thecontent of the present audio stream was originally designed or produced.In that sense it represents the optimal loudspeaker layout from thecontent creator's perspective.

‘interactivity_enabled’—This 1-bit Boolean flag shall indicate, when setto ‘1’, that the audio stream contains elements with associatedmetadata, which enable user interactivity. When set to ‘0’, the flagshall indicate that no user interactivity of any kind is available. Thisflag may be used to determine the need for initializing a user interfacefor audio interactivity.

‘preselection_info_present’—This 1-bit Boolean flag shall indicate, whenset to ‘1’, that the elements in the preselection_info( ) structure arepresent. When set to ‘0’, this flag shall indicate that the elements inthe preselection_info( ) structure are not present.

‘multi_stream_info_present’—This 1-bit Boolean flag shall indicate, whenset to ‘1’, that the elements in the multi_stream_info( ) structure arepresent and that the stream is part of a bundle of streams that togetherform an audio program. When set to ‘0’, this flag shall indicate thatthe elements in the multi_stream_info( ) structure are not present andthat the audio stream is a self-contained complete main stream.

‘primary_language_length’—An 8-bit unsigned integer field that shallspecify the length in bytes of the primary language supported in theaudio asset.

‘primary_language_byte’—An 8-bit unsigned integer field that shallcontain a UTF-8 character of the the language of the primary audiodialogue component. The primary language of an audio asset shall begiven by a language tag as defined by IETF BCP 47].

‘num_additional_languages’—This 8-bit unsigned integer field shallspecify the number of additional languages that are available withinthis stream. If this field is set to ‘0’, then no additional languagesare available.

‘additional_language_length’—An 8-bit unsigned integer field that shallspecify the length in bytes of the additional language supported in theaudio asset.

‘additional_language_byte’—An 8-bit unsigned integer field that shallcontain a UTF-8 character of the the language of an additional audiodialogue component that is available in the audio stream. The additionallanguage of an audio asset shall be given by a language tag as definedby IETF BCP 47.

‘accessibility’—This 8-bit unsigned integer field shall identify theaccessibility support carried in this audio stream. Accessibilitysupport is signaled for the primary language and, if available, for eachadditional language. If the stream contains audio components foraccessibility support, this is signaled with the following values forthis field: 0=no accessibility support, 1=Visually Impaired, 2=HearingImpaired, 3=Visually and Hearing Impaired, 255=unknown. The values 4 to254 are reserved.

‘emergency_information_present_flag’—A 1-bit flag, when set to ‘1’indicates that the audio asset contains an audio/aural representation ofemergency information and that the elements in theemerngency_information_time_info( ) structure are present. When set to‘0’ indicates that the audio asset does not contain an audio/auralrepresentation of emergency information and that the elements in theemergency_information_time_info( ) structure are not present.

In the example illustrated in Table 8A, ‘multi-stream_info( ) may bebased on example syntax provided in Table 10.

TABLE 10 No. of Syntax Bits Format multi-stream_info( ) {this_is_main_stream 1 bslbf this_stream_id 7 uimsbf reserved 1 ‘1’bundle_id 7 uimsbf if (this_is_main_stream) { reserved 1 ‘1’num_auxiliary_streams 7 uimbsf for(m=0; m< num_auxiliary_streams;m++) {delivery_method 1 bslbf auxiliary_stream_id 7 uimbsf } } }

In the example illustrated in Table 10, syntax elements‘this_is_main_stream’, ‘this_stream_id’, ‘bundle_id’,‘num_auxiliary_streams’, ‘delivery_method’, and ‘auxiliary_stream_id’may be based on the following example definitions:

‘this_is_main_stream’—This 1-bit Boolean flag shall indicate, when setto ‘1’, that this stream contains a main stream that can be presented onits own, or that can be combined with additional audio components froman auxiliary stream. When set to ‘0’, this flag shall indicate that thisstream contains an auxiliary stream.

‘this_stream_id’—This 7-bit unsigned integer field shall indicate the IDof this audio stream. This ID shall be unique within one bundle, i.e.,for all streams that have the same bundle id.

‘bundle_id’—This 7-bit unsigned integer field shall identify a unique IDfor one bundle of audio streams. A bundle consists of exactly one mainstream and one or more additional auxiliary streams that shall have thesame bundle_id. The auxiliary streams contain additional audiocomponents that can be combined with the main stream. The auxiliarystreams can be delivered via broadband or broadcast. The main streamshall always be delivered via broadcast and signaled within thisaudio_stream_properties_descriptor( ) with ‘this_is_main_stream’ set to‘1’.

‘num_auxiliary_streams’—This 7-bit unsigned integer field shall indicatethe number of auxiliary streams that are available on broadband orbroadcast to be combined with the main stream.

‘delivery_method’—This 1-bit Boolean flag shall indicate, when set to‘1’, that the corresponding auxiliary stream is delivered using DASH onHTTP. Access information to locate the stream is given in the DASH MPD.When set to ‘0’, this flag shall indicate that the correspondingauxiliary stream is delivered using MMT, signaled within the sameaudio_stream_properties_descriptor( ) and located through the asset idsignaled for this stream.

‘auxiliary_stream_id’—This 7-bit unsigned integer field shall identifythe ID of the auxiliary stream. The ID of all auxiliary streams shall beunique within one bundle.

It should be noted that with respect to Table 8A and/or Table 8B,emergency_information_time_info( ) may be signaled at the asset leveland/or at the preselection level and/or at the (primary and/oradditional) language level. In one example, whenemergency_information_time_info( ) is signaled at the preselection levelits presence may be controlled by the value of correspondingflag/indication e.g. emergency_information_present_flag included at thepreselection level, role included at the preselection level,accessibility included at the language level. In one example,audio/aural representation of emergency information start/end time andsignaling indicating its presence may be included at the (primary and/oradditional) language level only for assets. In one example, audio/auralrepresentation of emergency information start/end time and signalingindicating its presence may be included at the (primary and/oradditional) language level only for preselection. In one example IETFBCP 47 may corresponds to IETF Request For Comments (RFC) 5646. Itshould be noted that in some examples, in the case whereemergency_information_time_info( ) is included in preselection_info( )the values of ‘emergency_information_start_time_present’ and‘emergency_information_end_time_present’ may be inferred. In oneexample, ‘emergency_information_start_time_present’ and‘emergency_information_end_time_present’ included in preselection_info() may be based on the following definitions:‘emergency_information_start_time_present’—This one-bit Boolean flagshall indicate, when set to ‘1’, that the fields“emergency_information_start_time” and“emergency_information_start_time_ms” are present. When set to ‘0’, thefields “emergency_information_start_time” and“emergency_information_start_time_ms” shall not be present and the starttime of the aural/audio representation of the emergency informationshall be inferred to be equal to the presentation time of first mediasample in presentation order in the audio presentation [where sampleincludes an ISOBMFF sample].

‘emergency_information_end_time_present’—This one-bit Boolean flag shallindicate, when set to ‘1’, that the fields“emergency_information_end_time” and “emergency_information_end_time_ms”are present. When set to ‘0’, the fields“emergency_information_end_time” and “emergency_information_end_time_ms”shall not be present and the end time of the aural/audio representationof the emergency information shall be inferred to be equal to thepresentation time of the last media sample in presentation order in theaudio presentation [where sample includes an ISOBMFF sample].

As described above, with respect to Table 3, A/331 does not currentlydefine an audio stream properties descriptor and currently proposedaudio stream properties descriptor are less than ideal with respect towith respect to signaling language and accessibility information for apresentation.

Table 11 provide examples of syntax of anaudio_stream_properties_descriptor( ) message that may be generated by aservice distribution engine and parsed by a receiver device according toone or more techniques of this disclosure.

TABLE 11 No. of Syntax Bits Format audio_stream_properties_descriptor( ){ descriptor_tag 16 uimsbf descriptor_length 16 uimsbf number_of_assets8 uimsbf for (i=0; i<number_of_assets; i++) { asset_id_length 8 uimsbffor (j=0; j<asset_id_length; j++) { asset_id_byte 8 uimsbf } codec_code4*8 uimsbf number_of_presentations 8 uimsbf multi-stream_info_present 1bslbf emergency_info_time_present 1 bslbf reserved 6 ‘111111’ for (j=0;j<number_of_presentations; j++) { presentation_id 8 uimbsfinteractivity_enabled 1 bslbf profile_channel_conf_present 1 bslbfaudio_rendering_info_present 1 bslbf language_present 1 bslbfaccessibility_role_present 1 bslbf label_present 1 bslbf reserved 2 ‘11’if (profile_channel_conf_present) { if (codec_code == ‘ac-4’) {profile_level_indication 3*8 uimsbf audio_channel_configuration 3*8uimsbf } else { profile_level_indication 8 uimsbfaudio_channel_configuration 6 uimsbf reserved 2 ‘11’ } } 1 bslbf if(audio_rendering_info_present) { channel_layout_indication 2 uimsbfreserved 6 ‘111111’ } if (language_present) { num_languages_minus1 8uimbsf for(k=0; k< num_languages_minus1+1; k++) { language_length 8uimbsf for (l=0; l< language_length; l++) { language_byte 8 uimbsf } } }if (accessibility_role_present) { for(k=0; k< num_languages_minus1+1;k++) { accessibility 8 uimbsf } role 8 uimsbf } if (label_present) {label_length 8 uimsbf for(k=0; k< label_length; k++) { label_data_byte 8uimbsf } } if (multi-stream_info_present) {presentation_aux-stream_info( ) Table 16 } } /* end of fornumber_of_presentations loop*/ if (multi-stream_info_present) {multi-stream_info( ) Table 15 } if (emergency_info_time_present) {emergency_information_time_info( ) Table 14 } } }

In one example syntax elements ‘descriptor_tag’, ‘descriptor_length’,‘number_of_assets’, ‘asset_id_length’, ‘asset_id_byte’, ‘codec_code’,‘num_of_presentations’, ‘multi_stream_info_present’,‘emergency_info_time_present’, ‘presentation_id’,‘interactivity_enabled’, ‘profile_channel_conf_present’,‘audio_rendering_info_present’, ‘language_present’,‘accessibility_role_present’, ‘label_present’,‘profile_level_indication’, ‘audio_channel_configuration’,‘channel_layout_indication’, ‘num_languages_minus 1’, ‘language_length’,‘language_byte’, ‘accessibility’, ‘role’, ‘label_length’, and‘label_data_byte’ illustrated in Table 11 may be based on the followingexample definitions:

‘descriptor_tag’—A 16-bit unsigned integer field that shall have thevalue 0x0009, identifying this descriptor as theaudio_stream_properties_descriptor( )

‘descriptor_length’—A 16-bit unsigned integer field that shall specifythe length (in bytes) immediately following this field up to the end ofthis descriptor.

‘number_of_assets’—An 8-bit unsigned integer field that shall specifythe number of audio assets described by this descriptor.

‘asset_id_length’—An 8-bit unsigned integer field that shall specify thelength in bytes of the audio asset id.

‘asset_id_byte’—An 8-bit unsigned integer field that shall contain abyte of the audio asset id.

‘codec_code’—A 32-bit unsigned integer field that shall specify a4-character code for a codec.

‘number_of_presentations’—An 8-bit unsigned integer field that shallindicate the number of Presentations that are available within the mainstream and all auxiliary streams. The minimum number ofnum_presentations shall be ‘1’ for the main stream. For auxiliarystreams num_presentations shall have the value ‘0’ so that for auxiliarystreams no presentation information is present in the descriptor.

‘multi_stream_info_present’—A 1-bit Boolean flag that shall indicate,when set to ‘1’, that the elements in the multi_stream_info( ) structureare present and that the stream is part of a bundle of streams thattogether form an audio program. When set to ‘0’, this flag shallindicate that the elements in the multi_stream_info( ) structure are notpresent and that the audio stream is a complete main stream thatcontains all audio components of all presentations.

‘emergency_info_time_present’—A 1-bit Boolean flag that when set to ‘1’shall indicate that the elements in the emergency_information_time_info() structure are present. And that when set to ‘0’ shall indicate thatthe elements in the emergency_information_time_info( ) structure are notpresent. The value of this field shall be equal to ‘0’ when none of thePresentations in the audio asset contain an audio/aural representationof the emergency information.

‘presentation_id’—An 8-bit unsigned integer field that shall identifythe ID of this Presentation. The first presentation in the loop shall bethe default Presentation.

‘interactivity_enabled’—A 1-bit Boolean flag that shall indicate, whenset to ‘1’, that the audio presentation contains elements withassociated metadata, which enable user interactivity. When set to ‘0’,the flag shall indicate that no user interactivity of any kind isavailable. This flag may be used to determine the need for initializinga user interface for audio interactivity.

‘profile_channel_conf_present’—A 1-bit Boolean flag that shall indicate,when set to ‘1’, that profile and channel configuration information forthis Presentation is present. When set to ‘0’, this flag shall indicatethat no profile and channel configuration information for thisPresentation is present. The profile_channel_conf_present flag shall bealways set to ‘1’ for the default presentation.

‘audio_rendering_info_present’—A 1-bit Boolean flag that shall indicate,when set to ‘1’, that additional audio rendering info for thisPresentation is present. When set to ‘0’, this flag shall indicate thatno additional audio rendering info for this Presentation is present.

‘language_present’—A 1-bit Boolean flag that shall indicate, when set to‘1’, that language information for this Presentation is present. Whenset to ‘0’, this flag shall indicate that no language information forthis Presentation is present.

‘accessibility_role_present’—A 1-bit Boolean flag that shall indicate,when set to ‘1’, that accessibility and role information for thisPresentation is present. When set to ‘0’, this flag shall indicate thatno accessibility and role information for this Presentation is present.

‘label_present’—A 1-bit Boolean flag that shall indicate, when set to‘1’, that a text label for this Presentation is present. When set to‘0’, this flag shall indicate that the text label for this Presentationis not present.

‘profile_level_indication’—This field shall indicate the audio profileand level of the associated presentation, i.e. it indicates thecomplexity and decoder requirements.

‘audio_channel_configuration’—This field that shall indicate the audiochannel configuration of the encoded audio stream. A value of ‘0’indicates that a single audio_channel_configuration value is notmeaningful, because the encoded audio e.g. contains a combination ofaudio elements that are not channel-based, like audio objects that couldbe rendered to positions/coordinates independent from speakerconfigurations. Instead, the following field channel_layout_indicationmay be used to retrieve some meaningful information about the availablerendering options.

‘channel_layout_indication’—A 2-bit unsigned integer field that maycontain a hint for a preferred reproduction channel layout, if audiochannel configuration is set to ‘0’. Values of channel layout indicationshall be as specified in Table 12.

TABLE 12 channel_layout_indication value Meaning ‘00’ There is nopreference given for the reproduction channel layout. ‘01’ The contentis pre-rendered for consumption with headphones. In this case, thefollowing field reference_channel_layout shall be set to ‘0’. ‘10’ Thecontent has only elements to be rendered in a plane, i.e. the preferredreproduction channel layout is a two-dimensional layout ‘11’ the contenthas elements with heights, i.e. the preferred reproduction channellayout is a three-dimensional layout

‘num_languages_minus 1’—An 8-bit unsigned integer field plus 1 thatshall specify the number of languages that are available within thisPresentation. When not present the value of num languages minusl shallbe inferred to be equal to 0.

‘language_length’—An 8-bit unsigned integer field that shall specify thelength in bytes of each language supported in the Presentation. Thefirst language in the loop (k is equal to 0) shall be the primarylanguage for the Presentation. The remaining language(s) in the loop (kis not equal to 0) shall indicate the additional language(s) availablein the Presentation. In some examples, a primary language may include adefault language for a service and/or may correspond to an official ormost common (e.g., as determined by number of speakers) for a region(e.g., a country, a territory, or the like).

‘language_byte’—An 8-bit unsigned integer field that shall contain aUTF-8 character of the (k-th) language of each audio dialogue componentin this Presentation. The language of the Presentation shall be given bya language tag as defined by IETF BCP 47 (Internet Engineering TaskForce (IETF) Best Current Practice (BCP) 47) [BCP 47, September 2009].It should be noted that BCP is a persistent name for a series of IETFRequest for Comments (RFC) whose numbers change as they are updated. Thelatest RFC describing language tag syntax is RFC 5646, Tags for theIdentification of Languages, which is incorporated by reference herein,and it obsoletes the older RFCs 4646, 3066 and 1766. In RFC 5646, thelength of value of xml:lang is variable. It should be noted that inother examples, other language tags may be used.

In one another example, language byte may be based on the followingexample definition:

‘language_byte’—An 8-bit unsigned integer field that shall contain aUTF-8 character of the (k-th) language of the Presentation. The languageof the Presentation shall be given by a language tag as defined by IETFBCP 47 (Internet Engineering Task Force (IETF) Best Current Practice(BCP) 47) [BCP 47, September 2009]. It should be noted that BCP is apersistent name for a series of IETF Request for Comments (RFC) whosenumbers change as they are updated. The latest RFC describing languagetag syntax is RFC 5646, Tags for the Identification of Languages, whichis incorporated by reference herein, and it obsoletes the older RFCs4646, 3066 and 1766. In RFC 5646, the length of value of xml:lang isvariable. It should be noted that in other examples, other language tagsmay be used.

‘accessibility’—An 8-bit unsigned integer field that shall identify theaccessibility support for each language this Presentation. Accessibilitysupport is signaled for each language in this Presentation. The k-thoccurrence of accessibility element in this accessibility “for” loopshall indicate the accessibility information for k-th language in thelanguage “for” loop above. Table 13 specifies the bit used to indicateif the Presentation contains support for a particular audioaccessibility service. When the bit specified in Table 13 is set to ‘1’it indicates the Presentation contains the corresponding audioaccessibility service. When the bit specified in Table 13 is set to ‘0’it indicates the Presentation does not contain the corresponding audioaccessibility service.

TABLE 13 Bit Audio Accessibility Service 0 (MSB) For Visually Impaired 1For Hearing Impaired 2 Audio/Aural representation of EmergencyInformation 3-7 reserved Note: Bit 0, which indicates the presence ofthe audio accessibility service for visually impaired for thePresentation is the MSB of the accessibility field. For example, toindicate that the Presentation contains audio accessibility service forVisually Impaired as well as aural/audio representation of emergencyinformation, the value of the accessibility field would be 0xBF (thehexadecimal equivalent of the binary value 1011 1111).

‘label_length’—An 8-bit unsigned integer field that shall specify thelength in bytes of this Presentation text label.

‘label_data_byte’—An 8-bit unsigned integer field that shall contain abyte of the Presentation text label.

It should be noted that in the example illustrated in Table 11, thesyntax provided for specify the number of languages that are availablewithin a presentation and identifying each language in a presentationmay be particularly useful for efficiently indicating a language of aprimary dialogue of a service and indicating languages of one or moreadditional audio dialogue components. Further, the syntax for specifyingaccessibility support for each language with a presentation may beparticularly useful for efficiently indicating accessibility support.

As illustrated in Table 11, example syntax for‘emergency_information_time_info( )’ is illustrated in Table 14.

TABLE 14 No. of Syntax Bits Format emergency_information_time_info( ) {emergency_information_start_time_present 1 bslbfemergency_information_end_time_present 1 bslbf reserved 6 ‘11 1111’ If(emergency_information_start_time_present) {emergency_information_start_time 32 uimsbf reserved 6 ‘11 1111’emergency_information_start_time_ms 10 uimsbf } If(emergency_information_end_time_present) {emergency_information_end_time 32 uimsbf reserved 6 ‘11 1111’emergency_information_end_time_ms 10 uimsbf } }

In one example syntax elements‘emergency_information_start_time_present’,‘emergency_information_end_time_present’,‘emergency_information_start_time’,‘emergency_information_start_time_ms’, ‘emergency_information_end_time’,and ‘emergency_information_end_time_ms’ in Table 13 may be based on thefollowing example definitions:

‘emergency_information_start_time_present’—A 1-bit Boolean flag thatshall indicate, when set to ‘1’, that the fieldsemergency_information_start_time and emergency_information_start_time_msare present. When set to ‘0’, the fieldsemergency_information_start_time and emergency_information_start_time_msshall not be present and the start time of the aural/audiorepresentation of the emergency information shall be inferred to beequal to the presentation time of first media sample in presentationorder in the audio asset.

‘emergency_information_end_time_present’—A 1-bit Boolean flag that shallindicate, when set to ‘1’, that the fieldsemergency_information_end_time and emergency_information_end_time_ms arepresent. When set to ‘0’, the fields emergency_information_end_time andemergency_information_end_time_ms shall not be present and the end timeof the aural/audio representation of the emergency information shall beinferred to be equal to the presentation time of the last media samplein presentation order in the audio asset.

‘emergency_information_start_time’—A 32-bit unsigned integer that shallindicate the start time of the aural/audio representation of theemergency information, as the least-significant 32 bits of the count ofthe number of seconds since Jan. 1, 1970 00:00:00, International AtomicTime (TAI).

‘emergency_information_start_time_ms’—A 10-bit unsigned integer in therange 0 to 999 that shall indicate the milliseconds offset from the timeindicated in emergency_information_start_time, such that the formulaemergency_information_start_time+(emergency_information_start_time_ms/1000)yields the start time of the audio/aural emergency information to thenearest 1 millisecond.

‘emergency_information_end_time’—A 32-bit unsigned integer that shallindicate the end time of the aural/audio representation of the emergencyinformation, as the least-significant 32 bits of the count of the numberof seconds since Jan. 1, 1970 00:00:00, International Atomic Time (TAI).

‘emergency_information_end_time_ms’—A 10-bit unsigned integer in therange 0 to 999 that shall indicate the milliseconds offset from the timeindicated in emergency_information_end_time, such that the formulaemergency_information_end_time+(emergency_information_end_time_ms/1000)yields the end time of the audio/aural emergency information to thenearest 1 millisecond.

As illustrated in Table 11, ‘multi-stream_info( ) is illustrated inTable 15. In one example, if the multi-stream information is present,the audio program is delivered in more than one elementary stream, whereall streams that are part of a bundle of streams together form an audioprogram. In one example, the main stream shall always be delivered as anMMT broadcast stream. In one example, there may be two options todeliver auxiliary streams: within the MMT broadcast stream usingdifferent asset_IDs; they may be signaled within thisaudio_stream_properties_descriptor( ) or on broadband using DASHdelivery. In one example, a bundle_id and the stream_id shall be used tolink audio adapation sets in a DASH Media Presentation Descriptor (MPD)as auxiliary streams to this audio program.

TABLE 15 No. of Syntax Bits Format multi-stream_info( ) {this_is_main_stream 1 bslbf this_stream_id 7 uimsbf reserved 1 ‘1’bundle_id 7 uimsbf if (this_is_main_stream) { reserved 1 ‘1’num_auxiliary_streams 7 uimbsf for(m=0; m< num_auxiliary_streams;m++) {delivery_method 1 bslbf auxiliary_stream_id 7 uimbsf } } }

In one example, syntax elements ‘this_is_main_stream’, ‘this_stream_id’,‘bundle_id’, ‘num_auxiliary_streams’, ‘delivery_method’, and‘auxiliary_stream_id’ in Table 15 may be based on the following exampledefinitions:

‘this_is_main_stream’—A 1-bit Boolean flag that shall indicate, when setto ‘1’, that this stream contains a main stream that can be presented onits own, or that can be combined with additional audio components froman auxiliary stream. When set to ‘0’, this flag shall indicate that thisstream contains an auxiliary stream.

‘this_stream_id’—A 7-bit unsigned integer field that shall indicate theID of this audio stream. This ID shall be unique within one bundle,i.e., for all streams that have the same bundle id.

‘bundle_id’—A 7-bit unsigned integer field that shall identify a uniqueID for one bundle of audio streams. A bundle consists of exactly onemain stream and one or more additional auxiliary streams that shall havethe same bundle_id. The auxiliary streams contain additional audiocomponents that can be combined with the main stream. The auxiliarystreams can be delivered via broadband or broadcast. The main streamshall always be delivered via broadcast and signaled within thisaudio_stream_properties_descriptor( ) with ‘this_is_main_stream’ set to‘1’.

‘num_auxiliary_streams’—A 7-bit unsigned integer field that shallindicate the number of auxiliary streams that are available on broadbandor broadcast to be combined with the main stream.

‘delivery_method’—A 1-bit Boolean flag that shall indicate, when set to‘1’, that the corresponding auxiliary stream is delivered using DASH onHTTP. Access information to locate the stream is given in the DASH MPD.When set to ‘0’, this flag shall indicate that the correspondingauxiliary stream is delivered using MMT, signaled within the sameaudio_stream_properties_descriptor( ) and located through the asset idsignaled for this stream.

‘auxiliary_stream_id’—A 7-bit unsigned integer field that shall identifythe ID of the auxiliary stream. The ID of all auxiliary streams shall beunique within one bundle.

TABLE 15.5 Bit Audio Accessibility Service 0 (MSB) For Visually Impaired1 For Hearing Impaired 2 Audio/Aural representation of EmergencyInformation 3-7 reserved Note: Bit 0, which indicates the presence ofthe audio accessibility service for visually impaired for thePreselection is the most significant bit (MSB) of the accessibilityfield. For example, to indicate that the Preselection contains audioaccessibility service for Visually Impaired as well as aural/audiorepresentation of emergency information, the value of the accessibilityfield would be 0xBF (the hexadecimal equivalent of the binary value 10111111), where bits 3-7 are set to ‘1.’ It should be noted that in someexamples, cases maybe supported where reserved bits (here bits 3-7) are‘0’ as opposed to ‘1’. This may enable future support for certain typeof accessibility.

With respect to Table 15.5, it should be noted that, Visually Impairedmay correspond to Video Description Service, and Hearing Impaired maycorrespond to a dialog enhancement. In one example, a Video DescriptionService may be an audio service carrying narration describing atelevision program's key visual elements. These descriptions may beinserted into natural pauses in the program's dialog. Video descriptionmakes TV programming more accessible to individuals who are blind orvisually impaired. The Video Description Service may be provided bysending a collection of “Music and Effects” components, a Dialogcomponent, and an appropriately labeled Video Description component,which are mixed at the receiver. Alternatively, a Video DescriptionService may be provided as a single component that is a Complete Mix,with the appropriate label identification. In an example, the dialogenhancement service increases intelligibility of the dialog in an audioscene.

In one example, Table 15.5 specifies the bit used in accessibility fieldto indicate if the stream contains audio components for a particularaudio accessibility service. When the bit specified in Table 15.5 is setto ‘1’ it indicates the stream contains audio components to support thecorresponding audio accessibility service. When the bit specified inTable 15.5 is set to ‘0’ it indicates the stream does contain audiocomponents to support the corresponding audio accessibility service.

Referring again to Table 8B, if the multi-stream information is present,the audio program is delivered in more than one elementary stream. Thisstructure lists all IDs of auxiliary streams that carry audio componentsthat are required for a specific presentation. Table 16 provides andexample syntax for presentation_aux-stream_info( )

TABLE 16 No. of Syntax Bits Format presentation_aux-strcam_info( ) {num_presentation_aux_streams 8 uimbsf for(m=0; m<num_presentation_aux_streams;m++) { aux_stream_id 8 uimbsf } }

As illustrated in Table 11, ‘presentation_aux-stream_info( ) isillustrated in Table 16. In one example, if the auxiliary streaminformation is present, the audio program is delivered in more than oneelementary stream. The structure in Table 16 lists all IDs of auxiliarystreams that carry audio components that are required for a specificpresentation.

In one example, syntax elements ‘num_presentation_aux_streams’ and‘aux_stream_id’ in Table 16 may be based on the following exampledefinitions:

‘num_presentation_aux_streams’—An 8-bit unsigned integer field thatshall indicate the number of auxiliary streams that are required forthis specific Presentation.

‘aux_stream_id’—An 8-bit unsigned integer field that shall identify theID of the auxiliary stream that is required for this specificPresentation.

In this manner, service distribution engine 400 represents an example ofa device configured signal information associated with an audio streamaccording to one or more techniques of this disclosure.

It should be noted that in some examples, signaling of the condition “If(emergency_information_present)” and/or emergency_information_time_info() may occur at the stream-level in multi-stream_info( ) and/orpresentation_aux-stream_info( ) It should be noted that signaling of thecondition “If (emergency_information_present)” and/oremergency_information_time_info( ) at the stream-level may be beneficialin redistribution scenerios, as well as, scenarios where partialpresentations may be rendered at a receiver device. It should be notedthat in some examples, signaling of the condition “If(emergency_information_present)” and/or emergency_information_time_info() may occur at all the auxiliary streams-level (e.g. field‘auxiliary_stream_id’) in multi-stream_info( ) but not for the currentstream (e.g. field ‘this_stream_id’).

As described above, component encapsulator 402 may be configured toreceive one or more media components and generate media presentationbased on DASH. FIG. 5B is a block diagram illustrating an example of acomponent encapsulator that may implement one or more techniques of thisdisclosure. Component encapsulator 550 may be configured to generate amedia presentation according to the techniques described herein. In theexample illustrated in FIG. 5B, functional blocks of componentencapsulator 550 correspond to functional blocks for generating a mediapresentation (e.g., a DASH media presentation). As illustrated in FIG.5B, component encapsulator 550 includes media presentation descriptiongenerator 552 and segment generator 554. Each of media presentationdescription generator 552 and segment generator 554 may beinterconnected (physically, communicatively, and/or operatively) forinter-component communications and may be implemented as any of avariety of suitable circuitry, such as one or more microprocessors,digital signal processors (DSPs), application specific integratedcircuits (ASICs), field programmable gate arrays (FPGAs), discretelogic, software, hardware, firmware or any combinations thereof. Itshould be noted that although component encapsulator 550 is illustratedas having distinct functional blocks, such an illustration is fordescriptive purposes and does not limit component encapsulator 550 to aparticular hardware architecture. Functions of component encapsulator550 may be realized using any combination of hardware, firmware and/orsoftware implementations.

Segment generator 554 may be configured to receive media components andgenerate one or more segments for inclusion in a media presentation.Media presentation description generator 552 may be configured togenerate media presentation description fragments. It should be notedthat in some examples, a service distribution engine (e.g., servicedistribution engine 308 or service distribution engine 400) or specificcomponents thereof may be configured to generate signalling messagesaccording to the techniques described herein. As such, description ofsignalling messages with respect to media presentation descriptiongenerator 552 should not be construed to limit the techniques describedherein. Thus, component encapsulator 402 and/or service distributionengine 400 may be configured to generate MPDs and/or similar signalingdata according to one or more of the techniques described herein.

Referring to Table 4.5, above, the example ‘Preselection’ descriptorfails to provide information indicating whether an audio stream includesaudio content associated with emergency information and further fails toprovide information associated with audio content associated withemergency information. According to the techniques described herein, inone example, elements or attributes included in a ‘Preselection’descriptor of an MPD may indicate whether an audio stream includes audiocontent associated with emergency information and/or may further provideinformation associated with audio content associated with emergencyinformation.

In one example, the XML data fragment of a MPD (e.g., within a‘Preselection’ descriptor) may define a scheme id uri and a value tolabel an audio preselection as including an audio/aural representationof emergency on-screen text information. For example, the following XMLdata fragment may be used:

<Accessibility schemeIdUri=“tag:atsc.org,2016:audio”value=“Emergencylnformation”/>

In one example, for the scheme tag:atsc.org,2016:audio, the value of the@value attribute may defined as provided in the example of Table 17.

TABLE 17 Value Description EmergencyInformation The value indicates thatthe parent element contains audio/aural representation of emergencyon-screen text information.

It should be noted that in other examples, more values may be definedfor the example schemeldURl. It should be noted that in a manner similarto a ‘Preselection’ descriptor, an AdaptationSet and/or ContentComponentin an MPD may additionally or alternatively include an Accessibilitydescriptor indicating emergency information. Further, in some examples,a ‘Role’ element in an MPD may indicate whether an audio stream includesaudio content associated with emergency information and/or may furtherprovide information associated with audio content associated withemergency information. For example, one of the allowed values for a‘Role’ element in an MPD may indicate that the associated parent elementcontains audio/aural representation of emergency on-screen textinformation. In another example, a value attribute for a Role elementfor a pre-determined schemeldURl may indicate that the associated parentelement includes audio/aural representation of emergency on-screen textinformation. In one example, the associated parent element may include aPeriod element. In one example, the associated parent element mayinclude an AdaptationSet element. In one example, the associated parentelement may include a Preselection element. In one example, theassociated parent element may include a ContentComponent element.

In one example, the start and end time of a set of audio media segments(within a MPD period) of the track indicated by an ‘Accessibility’element may be required to be equal to the start time and end time ofaudio/aural representation of emergency on-screen text information. Itshould be noted that this example constraint may be based on arequirement that start and end of emergency information are known.Alternatively, in a manner similar to that described above with respectto Table 10, in some examples, the start and end time of audio/auralrepresentation of emergency on-screen text information may be includedas part of the ‘Accessibility’ semantics or other MPD semantics. Forexample, an MPD may include one or more of‘emergency_information_start_time_present,emergency_information_end_time_present’,‘emergency_information_start_time, emergency_information_start_time_ms’,‘emergency_information_end_time’ and/or‘emergency_information_end_time_ms’, as described above.

In one example, the presentation time of the first media sample inpresentation order of the Period corresponding to the ‘Accessibility’element indicating presence of emergency information may be required beequal to the start time of audio/aural representation of emergencyon-screen text information. In one example, the presentation time of thelast media sample in presentation order of the Period corresponding tothe Accessibility element indicating presence of emergency informationmay be required to be equal to the end time of audio/auralrepresentation of emergency on-screen text information. It should benoted that in the case where a ‘Role’ element in a MPD is used toindicated emergency information similar constraints with respect tostart time and end time of a set of audio media segments may be definedfor Role. It should be noted that in the case where a ‘Role’ element ina MPD is used to indicate emergency information similar constraints withrespect to start time and end time of a set of audio media segments maybe defined for Role.

In one example, the presentation time of the first media sample inpresentation order of the element X (where X may be ContentComponent orAdaptationSet or Preselection) corresponding to the ‘Accessibility’element indicating presence of emergency information may be required beequal to the start time of audio/aural representation of emergencyon-screen text information. In one example, the presentation time of thelast media sample in presentation order of the element X (where X may beContent-Component or AdaptationSet or Preselection) corresponding to theAccessibility element indicating presence of emergency information maybe required to be equal to the end time of audio/aural representation ofemergency on-screen text information. It should be noted that in thecase where a ‘Role’ element in a MPD is used to indicated emergencyinformation similar constraints with respect to start time and end timeof a set of audio media segments may be defined for Role.

FIG. 6 is a block diagram illustrating an example of a receiver devicethat may implement one or more techniques of this disclosure. That is,receiver device 600 may be configured to parse a signal based on thesemantics described above with respect to one or more of the tablesdescribed above. Further, receiver device 600 may be configured to parseinformation associated with an audio stream. Receiver device 600 is anexample of a computing device that may be configured to receive datafrom a communications network and allow a user to access multimediacontent. In the example illustrated in FIG. 6, receiver device 600 isconfigured to receive data via a television network, such as, forexample, television service network 304 described above. Further, in theexample illustrated in FIG. 6, receiver device 600 is configured to sendand receive data via a wide area network. It should be noted that inother examples, receiver device 600 may be configured to simply receivedata through a television service network 304. The techniques describedherein may be utilized by devices configured to communicate using anyand all combinations of communications networks.

As illustrated in FIG. 6, receiver device 600 includes centralprocessing unit(s) 602, system memory 604, system interface 610, dataextractor 612, audio decoder 614, audio output system 616, video decoder618, display system 620, I/O device(s) 622, and network interface 624.As illustrated in FIG. 6, system memory 604 includes operating system606 and applications 608. Each of central processing unit(s) 602, systemmemory 604, system interface 610, data extractor 612, audio decoder 614,audio output system 616, video decoder 618, display system 620, I/Odevice(s) 622, and network interface 624 may be interconnected(physically, communicatively, and/or operatively) for inter-componentcommunications and may be implemented as any of a variety of suitablecircuitry, such as one or more microprocessors, digital signalprocessors (DSPs), application specific integrated circuits (ASICs),field programmable gate arrays (FPGAs), discrete logic, software,hardware, firmware or any combinations thereof. It should be noted thatalthough receiver device 600 is illustrated as having distinctfunctional blocks, such an illustration is for descriptive purposes anddoes not limit receiver device 600 to a particular hardwarearchitecture. Functions of receiver device 600 may be realized using anycombination of hardware, firmware and/or software implementations.

CPU(s) 602 may be configured to implement functionality and/or processinstructions for execution in receiver device 600. CPU(s) 602 mayinclude single and/or multi-core central processing units. CPU(s) 602may be capable of retrieving and processing instructions, code, and/ordata structures for implementing one or more of the techniques describedherein. Instructions may be stored on a computer readable medium, suchas system memory 604.

System memory 604 may be described as a non-transitory or tangiblecomputer-readable storage medium. In some examples, system memory 604may provide temporary and/or long-term storage. In some examples, systemmemory 604 or portions thereof may be described as non-volatile memoryand in other examples portions of system memory 604 may be described asvolatile memory. System memory 604 may be configured to storeinformation that may be used by receiver device 600 during operation.System memory 704 may be used to store program instructions forexecution by CPU(s) 602 and may be used by programs running on receiverdevice 600 to temporarily store information during program execution.Further, in the example where receiver device 600 is included as part ofa digital video recorder, system memory 604 may be configured to storenumerous video files.

Applications 608 may include applications implemented within or executedby receiver device 600 and may be implemented or contained within,operable by, executed by, and/or be operatively/communicatively coupledto components of receiver device 600. Applications 608 may includeinstructions that may cause CPU(s) 602 of receiver device 600 to performparticular functions. Applications 608 may include algorithms which areexpressed in computer programming statements, such as, for-loops,while-loops, if-statements, do-loops, etc. Applications 608 may bedeveloped using a specified programming language. Examples ofprogramming languages include, Java™, Jini™, C, C++, Objective C, Swift,Perl, Python, PhP, UNIX Shell, Visual Basic, and Visual Basic Script. Inthe example where receiver device 600 includes a smart television,applications may be developed by a television manufacturer or abroadcaster. As illustrated in FIG. 6, applications 608 may execute inconjunction with operating system 606. That is, operating system 606 maybe configured to facilitate the interaction of applications 608 withCPUs(s) 602, and other hardware components of receiver device 600.Operating system 606 may be an operating system designed to be installedon set-top boxes, digital video recorders, televisions, and the like. Itshould be noted that techniques described herein may be utilized bydevices configured to operate using any and all combinations of softwarearchitectures.

System interface 610 may be configured to enable communications betweencomponents of receiver device 600. In one example, system interface 610comprises structures that enable data to be transferred from one peerdevice to another peer device or to a storage medium. For example,system interface 610 may include a chipset supporting AcceleratedGraphics Port (AGP) based protocols, Peripheral Component Interconnect(PCI) bus based protocols, such as, for example, the PCI Express™ (PCIe)bus specification, which is maintained by the Peripheral ComponentInterconnect Special Interest Group, or any other form of structure thatmay be used to interconnect peer devices (e.g., proprietary busprotocols).

As described above, receiver device 600 is configured to receive and,optionally, send data via a television service network. As describedabove, a television service network may operate according to atelecommunications standard. A telecommunications standard may definecommunication properties (e.g., protocol layers), such as, for example,physical signaling, addressing, channel access control, packetproperties, and data processing. In the example illustrated in FIG. 6,data extractor 612 may be configured to extract video, audio, and datafrom a signal. A signal may be defined according to, for example,aspects DVB standards, ATSC standards, ISDB standards, DTMB standards,DMB standards, and DOCSIS standards.

Data extractor 612 may be configured to extract video, audio, and data,from a signal generated by service distribution engine 400 describedabove. That is, data extractor 612 may operate in a reciprocal manner toservice distribution engine 400. Further, data extractor 612 may beconfigured to parse link layer packets based on any combination of oneor more of the structures described above.

Data packets may be processed by CPU(s) 602, audio decoder 614, andvideo decoder 618. Audio decoder 614 may be configured to receive andprocess audio packets. For example, audio decoder 614 may include acombination of hardware and software configured to implement aspects ofan audio codec. That is, audio decoder 614 may be configured to receiveaudio packets and provide audio data to audio output system 616 forrendering. Audio data may be coded using multi-channel formats such asthose developed by Dolby and Digital Theater Systems. Audio data may becoded using an audio compression format. Examples of audio compressionformats include Motion Picture Experts Group (MPEG) formats, AdvancedAudio Coding (AAC) formats, DTS-HD formats, and Dolby Digital (AC-3,AC-4) formats. Audio output system 616 may be configured to render audiodata. For example, audio output system 616 may include an audioprocessor, a digital-to-analog converter, an amplifier, and a speakersystem. A speaker system may include any of a variety of speakersystems, such as headphones, an integrated stereo speaker system, amulti-speaker system, or a surround sound system.

Video decoder 618 may be configured to receive and process videopackets. For example, video decoder 618 may include a combination ofhardware and software used to implement aspects of a video codec. In oneexample, video decoder 618 may be configured to decode video dataencoded according to any number of video compression standards, such asITU-T H.262 or ISO/IEC MPEG-2 Visual, ISO/IEC MPEG-4 Visual, ITU-T H.264(also known as ISO/IEC MPEG-4 Advanced video Coding (AVC)), andHigh-Efficiency Video Coding (HEVC). Display system 620 may beconfigured to retrieve and process video data for display. For example,display system 620 may receive pixel data from video decoder 618 andoutput data for visual presentation. Further, display system 620 may beconfigured to output graphics in conjunction with video data, e.g.,graphical user interfaces. Display system 620 may comprise one of avariety of display devices such as a liquid crystal display (LCD), aplasma display, an organic light emitting diode (OLED) display, oranother type of display device capable of presenting video data to auser. A display device may be configured to display standard definitioncontent, high definition content, or ultra-high definition content.

I/O device(s) 622 may be configured to receive input and provide outputduring operation of receiver device 600. That is, I/0 device(s) 622 mayenable a user to select multimedia content to be rendered. Input may begenerated from an input device, such as, for example, a push-buttonremote control, a device including a touch-sensitive screen, amotion-based input device, an audio-based input device, or any othertype of device configured to receive user input. I/O device(s) 622 maybe operatively coupled to receiver device 600 using a standardizedcommunication protocol, such as for example, Universal Serial Busprotocol (USB), Bluetooth, ZigBee or a proprietary communicationsprotocol, such as, for example, a proprietary infrared communicationsprotocol.

Network interface 624 may be configured to enable receiver device 600 tosend and receive data via a local area network and/or a wide areanetwork. Network interface 624 may include a network interface card,such as an Ethernet card, an optical transceiver, a radio frequencytransceiver, or any other type of device configured to send and receiveinformation. Network interface 624 may be configured to perform physicalsignaling, addressing, and channel access control according to thephysical and Media Access Control (MAC) layers utilized in a network.Receiver device 600 may be configured to parse a signal generatedaccording to any of the techniques described above with respect to FIG.6. In this manner, receiver device 600 represents an example of a deviceconfigured parse a syntax element indicating the number of aconcatenated syntax elements identifying a caption service, and parseone or more concatenated syntax elements identifying a caption service.

In one or more examples, the functions described may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored on or transmitted over as oneor more instructions or code on a computer-readable medium and executedby a hardware-based processing unit. Computer-readable media may includecomputer-readable storage media, which corresponds to a tangible mediumsuch as data storage media, or communication media including any mediumthat facilitates transfer of a computer program from one place toanother, e.g., according to a communication protocol. In this manner,computer-readable media generally may correspond to (1) tangiblecomputer-readable storage media which is non-transitory or (2) acommunication medium such as a signal or carrier wave. Data storagemedia may be any available media that can be accessed by one or morecomputers or one or more processors to retrieve instructions, codeand/or data structures for implementation of the techniques described inthis disclosure. A computer program product may include acomputer-readable medium.

By way of example, and not limitation, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. It should be understood, however, thatcomputer-readable storage media and data storage media do not includeconnections, carrier waves, signals, or other transitory media, but areinstead directed to non-transitory, tangible storage media. Disk anddisc, as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray disc wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, an integratedcircuit (IC) or a set of ICs (e.g., a chip set). Various components,modules, or units are described in this disclosure to emphasizefunctional aspects of devices configured to perform the disclosedtechniques, but do not necessarily require realization by differenthardware units. Rather, as described above, various units may becombined in a codec hardware unit or provided by a collection ofinteroperative hardware units, including one or more processors asdescribed above, in conjunction with suitable software and/or firmware.

Moreover, each functional block or various features of the base stationdevice and the terminal device (the video decoder and the video encoder)used in each of the aforementioned embodiments may be implemented orexecuted by a circuitry, which is typically an integrated circuit or aplurality of integrated circuits. The circuitry designed to execute thefunctions described in the present specification may comprise ageneral-purpose processor, a digital signal processor (DSP), anapplication specific or general application integrated circuit (ASIC), afield programmable gate array (FPGA), or other programmable logicdevices, discrete gates or transistor logic, or a discrete hardwarecomponent, or a combination thereof. The general-purpose processor maybe a microprocessor, or alternatively, the processor may be aconventional processor, a controller, a microcontroller or a statemachine. The general-purpose processor or each circuit described abovemay be configured by a digital circuit or may be configured by ananalogue circuit. Further, when a technology of making into anintegrated circuit superseding integrated circuits at the present timeappears due to advancement of a semiconductor technology, the integratedcircuit by this technology is also able to be used.

Various examples have been described. These and other examples arewithin the scope of the following claims.

<overview>

According to another example of the disclosure, a device for signalinginformation associated with an audio stream comprises one or moreprocessors configured to signal a syntax element specifying the numberof available languages within a presentation associated with an audiostream and signal one or more syntax elements identifying each of theavailable languages.

According to another example of the disclosure, an apparatus signalinginformation associated with an audio stream comprises means forsignaling a syntax element specifying the number of available languageswithin a presentation associated with an audio and means for andsignaling one or more syntax elements identifying each of the availablelanguages.

According to another example of the disclosure, a non-transitorycomputer-readable storage medium comprises instructions stored thereonthat upon execution cause one or more processors of a device to signal asyntax element specifying the number of available languages within apresentation associated with an audio stream and signal one or moresyntax elements identifying each of the available languages.

According to another example of the disclosure, a device for parsinginformation associated with an audio stream comprises one or moreprocessors configured to parse a syntax element specifying the number ofavailable languages within a presentation associated with an audiostream and parse one or more syntax elements identifying each of theavailable languages.

According to another example of the disclosure, an apparatus for parsinginformation associated with an audio stream comprises means for parsinga syntax element specifying the number of available languages within apresentation associated with an audio stream and means for parsing oneor more syntax elements identifying each of the available languages.

According to another example of the disclosure, a non-transitorycomputer-readable storage medium comprises instructions stored thereonthat upon execution cause one or more processors of a device to parse asyntax element specifying the number of available languages within apresentation associated with an audio stream and parse one or moresyntax elements identifying each of the available languages.

<Cross Reference>

This Nonprovisional application claims priority under 35 U.S.C. § 119 onprovisional Application No. 62/313,635 on Mar. 25, 2016, provisionalApplication No. 62/315,611 on Mar. 30, 2016, provisional Application No.62/319,209 on Apr. 6, 2016, and provisional Application No. 62/325,406on Apr. 20, 2016, the entire contents of which are hereby incorporatedby reference.

1. A method for signaling information associated with an audio stream,the method comprising: signaling a first syntax element specifying thenumber of languages that are available within a presentation associatedwith the audio stream; and signaling one or more second syntax elementsspecifying a length in bytes of each language supported in thepresentation, wherein the first syntax element has an integer value oneless than the number of available languages in the presentation. 2.(canceled)
 3. The method of claim 1, further comprising signaling one ormore characters containing a UFT-8 character of a k-th language of thepresentation, wherein the language of the presentation is given by alanguage tag as defined by IET BCP47.
 4. The method of claim 1, whereina first language specified by the one or more second syntax elements ina loop is a primary language for the presentation.
 5. The method ofclaim 4, wherein one or more remaining language specified by the one ormore second syntax elements in the loop indicates one or more additionallanguage available in the presentation.
 6. The method of claim 4,wherein the primary language includes a default language, an official,or a most common language of a region.
 7. The method of claim 1, furthercomprising signaling a third syntax element identifying an accessibilitysupport for the each language in the presentation, wherein theaccessibility support is signaled for the each language in thepresentation.
 8. The method of claim 1, wherein the audio stream isincluded in a MMT signaling message.
 9. (canceled)
 10. A device forsignaling information associated with an audio stream, the devicecomprising: one or more processors configured to signal a first syntaxelement specifying the number of languages that are available within apresentation associated with the audio stream; and signal one or moresecond syntax elements specifying a length in bytes of each languagesupported in the presentation, wherein the first syntax element has aninteger value one less than the number of available languages in thepresentation. 11-14. (canceled)
 15. An apparatus for signalinginformation associated with an audio stream, the apparatus comprising:service distribution engine circuitry that signals a first syntaxelement specifying the number of languages that are available within apresentation associated with the audio stream; and signals one or moresecond syntax elements specifying a length in bytes of each languagesupported in the presentation, wherein the first syntax element has aninteger value one less than the number of available languages in thepresentation. 16-39. (canceled)